Any suggestions on authoritative sources for neutral tones? The use of neutral tones in Skritter sometimes seems a little inconsistent, but it's not easy to compare similar words so I'm not really sure.

For example, 八竿子打不着 came up in my list again today. I was surprised the 不 is not a neutral tone. Sometimes words with postfixes such as 下去、上去 are also not quite as I intuitively expect.

I've found quite a handful of these (下去、上去 etc.); some of them were mistakes but a lot of cases the Taiwanese version uses the full tone for both, and since Skritter allows both mainland and Taiwanese options, it's very hard to tell. I find it very annoying and I almost always get neutral tones wrong, but short of separating Taiwan and mainland studying I don't know how they would fix it.

There have been many discussions of this in the past (search the forum for 'neutral') for example this one
http://www.skritter.com/forum/topic?id=91636697

Thanks Catherine, found this by searching:

http://www.skritter.com/forum/topic?id=172229506

Which covers a lot of the rules (although not the first one I mention above). Also some comments on emphasis in this thread:

http://www.skritter.com/forum/topic?id=47073189

and on Skritter's policy on some common neutral tones here:

http://www.skritter.com/forum/topic?id=189353558

For reference a link to (an unofficial copy of) the PSC list of compulsory neutral tones:

http://www.beijingputonghua.com/psc/qingsheng/qingsheng.htm

There is a paper here in Chinese that talks about different types of 轻声:

http://bit.ly/1pIj3YQ (used URL-shortener as Skritter's forum seems to choke on the UTF-8 URL)

Still not sure on whether the tones should change in some of the phrases like the above - in my head the bu4 is bu5. I think Skritter's policy is if a tone is neutral in mainland and not in Taiwan then show it as neutral but accept the Taiwanese reading as well, but not entirely clear on that.

The pronunciation of 不 in 打不着 is better considered in light of intonation. For a 3 characters word, the level of stress of each of the characters from left to right are classified as 中、次轻 and 重 respectively. So the middle 不 is read with a stress of 次轻. It is different from a neutral tone, which is 最轻 and carries no tone, but the resulting effect is very similar. It's just okey to think that it's a neutral tone and read it as such.

Thanks pts - I just checked the word list in Skritter and there is an entry for 打不着 with bu5, as well as the one above that's bu4. So this seems to be inconsistent in Skritter unless the stress is changed due to the position in the phrase.

Also 一面之词 - in Skritter 之 is neutral, in Pleco it is first tone - which is correct and which dictionary or word list is most authoritative for checking this? Another one: 说不过去 - Skritter has bu5 and qu5 but guo4. What is a good source on this?

The 不 between a verb and the verb's complement is always read so lightly that it sounds like a neutral tone, so I think that it's a good idea to always mark it as a neutral tone.

一面之词 should be read as [yímiànzhīcí]. When a need arises, most of the time, I'll consult the 现代汉语词典. This is because it is endorsed by 中国国务院，and all public exams held in mainland will use it as a reference.

过去has 3 entries in the 现代汉语词典. The one relevant to the present discussion is marked as [//·guò//·qù]. What this symbol means is that,
(1) after a verb, as in the case of 跑过去, both of the 2 characters 过去 are read very lightly.
(2) after a verb and the character 不 or 得, as in the case of 跑不过去, both of the 2 characters 过去 are read normally and not as neutral tone. (The 不 is read lightly.)
(3) like (2) above but with an extra character inserted between 过 and 去，as in the case of 跑不过他去，the 过 is heavily stressed and the 去 is read lightly.

So 说不过去 belongs to (2) above and its pinyin should be [shuō bu guòqù].

(I've put all the 3 pinyins for 过去 in the mnemonic field of the word 过去.)

pts - many thanks again.

Thanks pts! That's very helpful.

Another one I'm not sure of 歇不过劲儿来. Has lai5, but pleco seems to suggest lai2. Which is right?

Under the entry of 过去 mentioned earlier, the following 2 examples can be found. 鸡蛋还能硬得过石头去？| 天气再热、也热不过乡亲们的心去。These indicate that more than 1 character can be inserted between 过 and 去.
Since 过来 also has an entry which has a similar pinyin marked as [//·guò//·lài], so the 来 in 歇不过劲儿来 should also be 轻读。

Thanks again pts. I guess that should [//·guò//·lai]? I'm getting a much better handle on these.

One I'm still not sure about is when 一 is read as first tone. According to Skritter, "松了一口气" has yi1 as the pinyin for 一 (I would expect yi4), while 一口 has yi4. 吃那一套 has yi2， 一分耕耘一分收获 and 一天到晚 has yi4. Another: 一国 has first tone and 一家 has fourth. 一遍 and 一百 have second while 一月 has first.

Actually it should be [//·guò//·lái]. The tone mark is retained. 现代汉语词典is a paper dictionary, so I've to type every thing out.

Quoting the dictionary for the meaning of that [·lái]:
一般轻读、间或重读的字，注音上标调号，注音前再加圆点，如"因为"注作yīn·wèi，表示"因为"的"为"字一般轻读，有时也可以读去声。
Please note that the word used is 轻读 but not 轻声。

The // symbol indicates that characters can be inserted in that position.

The pinyin standard states that sandhis are not shown unless it's for teaching purposes. So, all the 一's in the 现代汉语词典 and PSC lists are marked as 1st tone. But the sandhi rule for 一 is quite simple. It is yì before the 1st, 2nd or 3rd tones, but yí before a 4th tone. A lesser known exception is that when 一 is used as an ordinal number, then it is read as yī. 第一口 (the first bite) is yī, so are 一月一日 (January 1) , 一九九九 and 一年级.

This means that more than one reading (一日: the first day of the month？ the whole day？) may exist and a context is required to determine what is correct.

Quoted from the book, 普通話九大簋 by 香港中文大學普通話教育研究及發展中心

在百、千、万等数位前，"一"要变调，读成yì百、yì千、yí万。如果是连读的数字，只有开头的"一"需要变调，中间和末尾的都不变。例如："一万一千一百一十一"，只有万前的"一"变调读成yí，其余的都不变。