I choose to write this reply in English because if I write in Vietnamese, it must be in the new Vietnamese2020 in which all poly- and dissyllabic words will be combined according to their true nature. This kind of writing has annoyed many people of conservative camp in this forum. If you wish to know more about this matter, you can always refer to my Vietnamese2020 proposal at http://www.vny2k.net/CaitoCachVietTiengViet-UniEng.htm. This writing is also posted at http://vny2k.net/Ykien/Comments-NguyentacTruytimTunguyenHanNom.htm at the same time.

Like you, I am well aware that today's belief is going strongly more for theories of an Austroasiatic origin of Vietnamese than for those of older Sino-Tibetan camp. However, please bear in mind that the current hypotheses about the Mon-Khmer origin of Vietnamese is still only another theory, not quite proven yet. The Sino-Tibet school of thought is still holding ground for its prior theoretical merits, still worth being recapped and explored further if we can come up with solid proofs to prove otherwise and if we have anything to say about it.

I feel that I have been lucky for having been exposed to the Chinese language in some scholarly fields for quite a long time which has further strengthened my my knowlege of Vietnamese etymology and my conviction of the Sino-Tibetan connections. It is from my latest discovery that I have initially started out and then found way to build my theories around that belief. In fact, in that expedition I unexpectedly found out that the Vietnamese and Chinese languages have so much to share than any other Mon-Khmer languages as have been suggested so far that they all were originated from the same root as that of Vietnamese.

Being totally fascinated by this subject I have tried to study both Vietnamese and Chinese historical linguistics and been compelled to the ideas of tracing etymological proofs for many Nôm words of Chinese origin. In the process of working on this research, I have recorded substantial findings and have started to theorize them. With a conviction after having found that Nôm words are having so much of Chinese connections. I am determined to persue this goal by setting forth a new expedition going for the Sino-Tibetan direction. Hopefully my final work will give the Vietnamese etymology a new perspective

In deed, in the process of following Chinese traces of many Vietnamese words, I have found numerous Vietnamese words that are quite similar to those of Chinese commonly used in a colloquial manner that suggests something subtle about their kinship beside the cultural context that both the Vietnamese and Chinese share. Let's consider a few examples:

• chào 早 zăo
• đó: 那 ná (nớ - tiếngHuế dialect)
• rồi, nổi: 了 le, liăo (không quên nổi: 忘不了! wàng bùliăo!, quên rồi: 忘了 wàngle!)
• sẽ: 将 jiāng (sosánh: 酱油 jiāngyóu, Canonese: xìdầu)
• vẫn: 仍 réng
• huì: hội, họp, hẹn, hụi...
• lòng (also: tim): xīn (< tâm Cantonese sòm, old Vietnamese form: lâm)
• mắt 目mù, mat (mắtkiếng 目鏡 matkeng - Hainanese)
• biết (?): bat (Hananese)
• gàtrống 雞公 jīgōng (Hainanese and Fukienese or Amoy),
• 雞母 jīmǔ: gàmái (Fukienese)
• soài (?) suã (Fukienese)
• tầmbậy 三八 sānbā (tầmbạ, sàbát...)(Fukienese)
• cùlét (?): galet (Hainanese) (= thọclét, chọccười 逗笑 dòuxiào)
• đừng 甭 péng (Beijing dialect)
• mai 明兒 mínr (Beijing dialect)
• luônluôn 老老 láoláo (Beijing dialect)
• phở 粉 fén (also: bún, bột, phấn)
• nào: 哪 nă
• sījī : 司機 tàixế
• lēsē (lājī) 垃圾: rácrưới, rácrến
• quánzuò: 犬坐 chồmhổm (ngồi)
• yíngchóng: 婬虫 dêxòm (hence giving rise to another alternation "quỹrâuxanh" yíngchóngguǐ)
• đạochích: 盗贼 dàozéi
• đánhcắp: 打劫 dăjié and so on...

I have been collecting this kind of data over the past 20 years and I am now trying to put these pieces of puzzles together. Hopefully this work will not take 20 more years to complete even though the pace that I am progressing now is quite slow, doing the work part time and past time, and my work has just barely started.

Though the words listed above does not give you all the basic words as one would expect, at least many of those culturally flavored words suggests some unique vocabularies that Chinese and Vietnamese both share in common and daily speech. No other Mon-Khmer languages have come close in this respect.

Unsurprisingly many people may not make connections with some of the examples cited in some of my writings because those words do not look like cognates at all simply because parts of those words, either an initial or ending, do not show similarities.

In historical linguistics, you cannot always find denifinte one-to-one correspondences in initials, endings and/or finals (a whole syllabic final part of a word such as -at, -ang, -uyen, etc.), since over a span of more than 2000 years as in the case of Vietnamese and Chinese. Unless it is a later loan words or development vocabularies of the same source have evolved in each own way and readily changed to suit local speech habits of the Vietnmemse right after the first adoption of the very words it borrowed . However, as the time went by sound changes must have occurred according to the linguistic rules of sound changes, for example:

• wān 灣: loan (Sino-Vietnamse or HV while Nôm: vịnh), 
• xì 惜: tiếc (HV: tích), 
• xì 吸: hút (HV:hấp), 
• qì: hơi, 
• jí 集: tập, 
• xiě 寫: tả (HánViệt), 
• xué 學: học (HV, Cantonese: hòhk, Hainanese: faht), 
• yì 議: nghĩa (HV), 
• mín 民: dân (HV), 
• míng: 名 danh (HV), 
• ping 娉: sính (HV), 
• yì 藝: nghề (HV: nghệ), 
• yì 臆: ngực, 
• yì 憶: nhớ, 
• chì 吃: ăn, xơi (HV: ngật, sosánh 乙"ất"), 
• chéng 承: thừa, 
• thính 聽: nghe (Hainanese: khe), 
• sheng 生: đẻ (Hainanese: die), 
• qián 前: trước (Hainanese: tǎi), 
• xízăo 洗澡: tắmrữa (Hainanese: tòyăht)... 

Look at these samples we can alway draw patterns with that sound changes have taken place.

Take a closer look, we will see that many of them have been changed beyond recognition as both initials and endings, including finals, were dropped and changed completely.

As a matter of fact, sound changes might have occurred in patterns following strict linguistic rules as clearly shown in Sino-Vietnamese lexicons (từ HánViệt) which are easier to draw finite rules of sound changes systematically while with the older colloquial Vietnamese Nôm words it is much more difficult to do so. Another aspect of the sound chang matter should be considered is that most of the Nôm are not directly derived from those of Sino-Vietnamese or HánViệt words, even though they are closely related, but from a spoken Chinese dialect spoken at a certain time and place in history, many of them are much older than the Sino-Vietnmese words, for example: buồng (phòng) fáng, buồm (phàm) fán, chài (la) luó, cộ (xe) chē, bụt (phật) fóu, bua (vua < vương) wáng, bụa (vợ < phụ), etc.

When seeing I am illustrating modern Mandarin pinyin transcription, one may aks why Vietnamese has to do with Mandarin since the time Vietnam had already gained it independence from China in the 10th century while Mandarin is a spoken Northern dialect having come into its present state since the Northern Song's Dynasty, in the 11th century? In this aspect, Mandarin may not be a good pick to do the comparative work in historical linguistics because it, in fact, has changed so much, for instance its tonal system being reduded to 4 tone instead of 8 tone system and less in syllabic finals, due to the influence of some foreign northern languages, such as those spoken by the Kims (ancestors of the later Manchurians) and Mongolians, in comparison with other dialects such as Cantonese (a Chinese dialect with a 9 tone system) or Fukienese (7 tone system), which are still retaining many ancient peculiarities in, beside tones, much more syllabic finals.

However, I have picked Mandarin because today it is an offical language of China that many people come to contact with, so it is easier to relate and it is from this language that I have found all the living proofs that can be used to make my case, for example, chào 早 zǎo, mai 明兒 mínr, đừng 甭 péng (Beijing dialect), etc., that implitcitly suggests that many of Vietnamese Nôm did have something to do with some northern spoken dialect which might have developed from Middle Chinese, which later has become the Sino-Vietnamese lexicons.

That northern dialect is likely Mandarin, as a dynamic and lively language -- which language is not?--, with it's sounds having changed tremendously over the time, it shows all traceable linguistic rules of sound changes just as those of Sino-Vietnamese or HánViệt lexicons. In the meanwhile "pure" Vietnamese words, but traceably of their Chinese origin, or HánNôm, which are commonly used in a much more colloquial manner than in scholarly and literary form by all the Vietnamese people, must have also changed according the same linguistic rules, externally and internally. Putting them together we will have an overall etymological picture of sound-change patterns for us to examine. Starting from this premise I traced back the etymology to the ancient and archaic forms of Nôm by employing comparative historical linguistic mechanisms.

As a matter of fact, the purpose of my work is not to prove the Sino-Tibetan origin, but only to find the etymology of thousands of Nôm words. My approach is to apply deducing and analogical methodology to all candidate patterns of sound changes to draw the rules for all possible alterations of words from Chinese to Nôm. By doing so I believe that we will be able to find reliable traces of sound changes.

For the time being and for the purpose of a short discussion, just take some of may findings at their face values, i.e., -ang > -at, -ong > aw, n- > d-, etc. even though sound changes do follow linguistic rules which cannot fully explained here. The main principle to bear in mind is that sound changes did occur in "batches" or cluster of sounds such as -ương > -ang, -ong > -aw, -ang > -at, -at > an, etc. in a much later development and as Chinese has become more and more disyllabic in nature at a later time, its disyllabic words when changed into Vietnamese also have changed in dissyllabic clusters of sounds, not singly as simple vowels into other vowels or an initial into another initial. This is an important point in my new approach in search for Vietnamese etymology of Chinese origin. Only in this context can one be able to see how the sound changes have happened and been they way they are. In other words, disyllabic words carry along with their disyllabic characteristics when they transformed themselves in Vietnamese, for example with qì we have "hơi" as in qìchē: "xehơi", but with shengqì we have "tứcgiận", jiārén: "ngườinhà" (in reverse order to fit into local speech habit.), but with rénjiā, jiā becomes "ngườita", dàjiā: "tấtcả", báirì: "banngày", bachăng: "bạttai", 隐私 yǐnsi: "riêngtư", etc. As we can see the magnitude of sound changes are multi-faceted and diverse when dissyllabic words are treated as in whole unit whereas the same portion that stands alone as a monosyllabic word would not affect the whole string of sounds of dissyllabic words. If one still considers Vietnamese is a monosyllabic language, then s/he will never fully appreciate the underlined notion of these hyphotheses. Once accepting this principle, one will never wonder why -ư corresponds to -a, -iê to -a, -au ~ -ông, -at ~ -an, -an ~ -ôt, -ai ~ ua, etc, or will insist on -a- must be -ươ-, -ng must be -ng, or d- must be n- etc. on one to one relationship. In fact, sound changes did happen within linguistic contraints following certain patterns and, of course, in a linguistic kinship boundary, e.g., English "six" and Vietnamese "sáu" obviously are not cognates, but "lìu" and "sáu" might be given the the historical context of linguistic development of Vietnamese which has been going hand in hand with the evolution of the Chinese language, of which the vast vocabularies have penetrated into the Vietnamese language at different times and with virious dialectal contacts.

Specifically in reply to your questions, few of my sketchy notes presented here in any cases should not be considered inclusive and final -- many points are still questionable and nearly impossibly to prove or reverse, as just pointed out by you, numeral counting in Vietnamese from 1 to 5 are undeniably Mon-Khmer cognates because of their indisputable fact that there is a clear connection to those of Mon-Khmer languages. However, the fact that the Mon-Khmer numerals are based on the system of five and in Old and Modern Khmer there exist loaned elements of Thai counting system, such as 10,000 , which in turn are cognate to those of Chinese, may make one wonder why the Vietnamese counting system is based on ten instead of five just as those of the Mon-Khmer languages. Does it mean that the V first borrowed or initially had one to five then borrowed "sáu" to "mười" from the Chinese later on? Furthermore, one cannot solely base on similarity in numeral counting to draw any conclusion in genetic relation.

Now let's play with some the numbers first to establish some rapports and a sense of sound change patterns. This will not count, but what is behind them are valuable resouces for working with most of other words.

The fact that counting system in the Mon-Khmer languages is based on the system of five sheds doubt on a whole Vietnamese numeral set. Furthermore, the question of the origins of theVietnamese numerals sáu to mười will point to somewhere else. We have the right to suspect the Chinese numerals to have something worth speculating. Let's examine these patterns:

1. 六 lìu ’six’ sáu,
2. 七 qī 'seven' bảy
3. 八 bā ‘eight’ tám,
4. 九 jǐu ‘nine’ chín,
5. 十 shí ‘ten’ mười.

1) l- ~ s- correspondences are numerous:

蓮 lián ‘lotus’sen,
浪 làng ‘wave’ sóng,
亮 liàng ‘bright’ sáng,
郎 láng ‘man’ chàng,
螺 luó ‘clam’ sò,

2) The Sino-Vietnamese sound for qi ¤C is thất and we also have

匹 pǐ ‘mate’ SV thất,
必 bì ‘have to’ SVtất,
畢 bí ‘accomplish’ SV tốt,

which loosely gives us the t(h):p(h) corresponding relationship.

However, this deduction is a highly questionable case such as in the case of ba ‘three’ and bốn ‘four’ if any correlation between Chinese and Vietnamese numerals can be established at all. Compare ba (Nôm) and tam (SV) ‘three’ ¤T sān with Hainanese ta and if both Chinese sān and Vietnamese ‘ba’ really are cognates it looks like ba had undergone a process of dropping -m and change s- (or t-) to b- or as I see it. It that is the case, it is more likely that it is a dissimulating process that shifted the rounded ending -wm to the front and labialized to become b- [cf. Middle Chinese sam < *som, Proto-Chinese *sawm, Tibetan gsum, gsum-po ‘third’]. The idea that the transfer of rounding from the final labial to the initial is not mine alone, but also by Baxter’s as adopted by Bodman in his study. If the reasoning is right, ba must be very archaic. Reversibly, there is a pattern that shows a correspondence with modern Mand. p- and SV s-:

娉 pìng: ‘seek a marriage’ sính,
漂 piāo ‘float’ phiêu ,

and Mand. p- and Nôm s-:

怕 pà ’afraid’ sợ,
比 bǐ ’compare’ so, (as in bǐfāng: sosánh)

Interestingly the same patterns also appears in disyllabic words:

比肩 bǐjiān ‘to shoulder’ sátcánh

并肩 bìngjiān ‘to shoulder’ sánhvai

傍晚 bángwăng ‘dusk’ chạngvạng

起源 qǐyuán ‘originate’ bắttnguồn

起头 qǐtóu ‘start’ bắtđầu
and the pattern repeats itself internally in each language:

骋 chéng ‘gallop’ (cf. 娉 pìng) SV sính, Nôm phóng

津 jin ‘river bank’ (cf. µ§ bi) SV tân, Nôm bến

The sound change from Chinese labials to Vietnamese dentals is noted and speculated by several linguists such as Maspero and Karlgren (giving no explanation), Arisaca Hideyo and Paul Nagel as noted by Pulleyblank (1984). According to Pulleyblank, the whole sound change process can be summed up as follows:

Vietnamese t- was derived from s < ts < < psi < pci as if they are from ts. Forrest (1958) credited to Ancient C pj-, bj- and the process of palatalization before certain words beginning with s- were borrowed in V. The reverse process of s>p therefore can be deduced.

If the cases of bảy and barepresent anything meaningful,
四 sì 'four' SV tứ [tij] Nôm bốn
must have gone through the same process.

If the cases of ba, bốn, bảy are correct, tám should fit into the same corresponding pattern b- ~ t-.

3) j ~ c seems to justify the case by itself: jǐu ~ chín. In fact, the corresponding patterns are easy to find: jiān: chiên; zóu: chạy, jiăo: chân; zhao: cháy, zhèng: chính;

4) s (x, q,j) ~ m can be established as follows:
鹹 xián: mặn
請 qǐng : mời
慶 qìng : mừng...

If numerals ‘six’ to ‘ten’ in V are truly related to those in C as demonstrated in the above list, we have the right to doubt the genuineness of the first five numbers being originated from MK. This hypothesis is underlined by the supposition that the more ancient the roots are, the more likely that sounds have changed more drastically, sometimes beyond recognition and losing all the phonetic traces. This is surely contrary to the common belief that basic words are more static than others. Here is not a place to argue, but just imagine languages of the same root started out with the same basic words at a very early ancient stage and each one developed each own way during a span of many thousand years, probably from a language of initials of consonantal clusters without tone to languages with simple initials and tones as known in many Sino-Tibetan languages such as today's Chinese and Daic languages. That is true in the context that language is not fossilized and constantly in dynamic change to evolve from primitive to sophisticated stages, especially for those that must have undergone drastic change from toneless consonantal clusters to tonal system to differentiate meanings, in this case, monosyllabic ancient Chinese.

If the illustrations of the cases sáu, bảy, tám, chín, mười are convincing enough, let’s take a quick glimpse of many other patterns that repeat between Chinese and Vietnamese in the case bảy, ba, bốn and even một ‘one’, hai‘two’, năm ‘five’, I will give out a short list, which, like other cases illustrated above, is by no means exhaustive:

1) một  ‘one’ < nhất (SV) < MC [cf. jat (Cantonese)].

2) hai  ‘two’ < nhị [nhei] (SV) < MC jhei

3) năm  ‘five’ < ngũ (SV) < MC [cf. m'h (Cantonese)]

In any cases, the weakness of the points debated about the origin of numerals in Vietnamese is obvious, the Vietnamese "một" to "năm" is much more in closely resemblance with those of Mon-Khmer languages while keeping distance with those of Chinese. Again, what has been discussed so far in Vietnamese numerals is just a suggestive approach in searching for the Vietnamese etymology of Chinese origin of other words, which cannot be all wrong, but not in the analysis of the numbers themselves. Just as I have mentioned originally in my writing that nothing about the number is certain.

However, while acknowledging the resemblance of numerals and other words in Vietnamese and other Mon-Khmer languages we must recognize that lexicons of the Mon-Khmer languages are closer among themselves than with Vietnamese. This linguistic imprint may not in any way be used to deny other connections between Chinese and Vietnamese in most of other words. But here is a word of caution, "too close a likeness is even more suspicious than too distant a one." (Forrest 1958)

Now, let's go on with some other examples that you have cited:

For "răng", it is mostly a deduction from the words that are related to Chinese words for body parts in Vietnamese: tóu: đầu, lỗtai: ěrduo, mù: mắt, miàn: mặt, méi: mày, bì: mũi, hán: cằm, fá: tóc, xǖ: râu, húlóng: cổhọng, fèi: phổi, yì: ngực, xin: tim, gan: gan, shèn: thận, chăng: tay xiōng: hông, fú: bụng, tuǐ: đùi, zú: cẳng, jiăo: chân, etc.

Phonologically, we have răng 牙 (tooth): ngà (SV), yá (Mand.), ngah (Cant.), gheh (Hai.) and the pattern:

1. y - ~ ng- ~ r- : (the pattern: 硬 yìng: rắn, 阮 ruăn (nguyễn) ~ 元 yuán; 悒悒 yìyì: rayrứt; 耀 yáo: rọi; 隐 yǐn (riêng) as in 隐私 yǐnsi: riêngtư; 夭夭 yaoyao: rậmrạp; 蝇 yíng: ruồi (nhặng)... <2p>2. a ~ -ang: dă: đánh ("quánh" [wánh]), mà: mắng, dé: đặng (< được, dak Hainanese), 月 yuè: nguyệt, giăng, 日 rì: nhật, giời,

From yá, the Chinese compounds also give rise to some dissyllabic words: quányá "răngkhểnh"; yáròu: nướurăng (the order is in reverse), 牙齿 yáchǐ: "răngcỏ"...

For yá ~ răng, please read below:

For mặt, we have mặt 面 (face): diện [jien6](SV), miàn (Mand.), <*mjen [*-jen > denasalized to -jat], and the patterns of 吃: ăn SV ngật, cf. 乙"ất", modern Mandarin: chì = xơi; 咽 yàn = nuốt; 粉 fén: bột; fēn: phút, 淡 dàn 淡: nhạt, lạt; yùn 晕: ngất, mài 麦: mạch; mài 脉: mạch; mù 目: mắt; mò 默: mặc; mì 密: mật; mù 木: mộc; mò 没: một... From this pattern, we can safely establish a miàn ~ mặt correspondence.

For cá, it corresponds to Archaic Chinese *nga. The etymology: 鱼 cá  ‘fish’ yú <*nga [*ng- > Nôm k-; ** ng- > MC ngjw- > SV ngư]. The pattern ng- ~ k- is very common in linguistic sound changes, which can also occur via intermodals g-, gh-, kh- etc., such as kê > ji 鷄 > gà). Also, from cá we have: đánhcá: dăyú, dádǔ: cáđộ, yúcì: xươngcá,

lửa 火 (fire): hoả (SV), huǒ (Mand.), fó (Cant.) (the pattern w ~ l: cảlũ: 大伙 dàhuǒ; 同伙 tónghuǒ: đồngloã; 过 guò: quá [wa], lỗi; wan 灣: loan; 裸体 luǒtǐ: loãthể ~ 果 guǒ: quả [wa])

gạo 槄( rice): tháo (SV), tào (Mand.)"
g- and th-?

đất 土 (soil): thổ (SV), tǔ (Mand.): tǔ ~ đất sound change can fit into the following patterns:

tǔ: đất; tù: đột; tù: dú: độc; dù:đốc; hù: hốt; bù: bất; bì: tốt, bì: tất; gǔ: cốt

t- ~ đ- = táng: đường; tán: đàm; tán: đàn; tuǐ: đùi; tòng: đau; tóu: đầu; tǎ: đạp; tiẽ: điệp; tú: đồ; tiáo: điều... (Note: in Chinese dì ~ địa, a later development, is a doublet of tǔ, which can be used to further strengthen the case tǔ=đất, for example, for both tǔdì 土地 and dìdài we have đấtđai, dìmiàn 地貌 mặtđất, dìkuài 地块 cụcđất, vùngđất 地域 (the order is in reverse) )

For shao (thiêu) ~ đốt, đốt 燒 (to burn): thiêu (SV), it is not hard to see that sh- or th- (or s- for that matter) can give rise to đ- if we take into consideration the case of an alternation of shao, that is "sốt" as in fàshào "phátsốt" and "thắp" as in shàoxiang "thắpnhan, thắphương", which is the same as "đốtnhan, đốthương". Also, a reduplication of shao(+shao) has added a new word "thiêuđốt" into the Vietnamese vocabulary. (The same pattern occurred for shăo ~ thiếu // sót > "thiếusót", that is the same as quèshăo.)

Besides the patterns th- ~ đ- as given in the examples above to connect tǔ with "đất", that is "thiêu" ~ "đốt" where sh- usually gives rise to th-, which could be originally evolved from an archaic đ- (the Nôm word "đốt" must be an older form of "thiêu" since this sound did exist in archaic and ancient Chinese and still exists in some Chinese dialects such as Hananese or Amoy while "thiêu", a Sino-Vietnamese or HánViệt word, is a variation of Middle Chinese), we can also find other examples in the pattern sh- ~ đ instead of th- ~ đ-:

sh- ~ đ- = shuǐ: đák (nước), shuǐ > tă > đạp;

con 子(son): tử (SV), zi (Mand.), ke (Hai.)

sao 星 (star): tinh [teinh] (SV), xing (Mand.), Hananese: se ;

lúa 來 (whole rice grain): lai (SV, archaic), lái (modern Mand. means "come"): lúa ~ lai, lại,

This is a case similar to vi 爲 wēi: voi.

lá 葉 (leave): diệp (SV), yè (Mand.) y <*lja [*lj- > Mand. j-]

For "blời", 'blăng" they might have been just alternations of "mặttrời" and "mặttrăng" where b have been vocalized as "mặt". Otherwise, "giời" rì and "giăng" yè can not fit into a sound change scheme where gi- corresponds to both r- and y-, which, in turn, might have been evolved from some ancient sounds that must have been close to the initials nh-, j-, jh- and ng- as we can see in HánViệt "nhật" and "nguyệt" (Cantonese /jǎht/ and /jǎht/.)