I was thinking about how slight changes in pronunciation are reflected in writing.
As a case in point, here are two examples of words whose pronunciations are different, but similar, and whose meaning is the same. (Based on a few dictionaries like ABC and 现代汉语规范词典).
嫉妒 ji2du4 / 忌妒 ji4du5 Verb: be jealous of; hate
Is this a regional variation? Or is it the case that some people will sometimes use one pronunciation, and sometimes the other, depending on the context or on their mood?
嘟囔 du1nang5 / 嘟哝du1nong5 Verb: mutter/mumble to oneself The entry in现代汉语规范词典 for 嘟哝 says现在一般写作“嘟囔”.
Does anyone really make a distinction between du1nang5 and du1nong5? Is there an audible difference? And, if the answer is yes, then how about answers to the questions I asked regarding the "jealous" pair?
This phenomenon could be called “synonyms that are nearly, but not quite, homophones”. I would be interested in other examples. Are there any other notable ones? I have a feeling there may well be around a dozen examples commonly used in 普通话. (Still, as an intermediate student I realise I may well be wrong.)
(A related phenomenon is two different pronunciations of the same character, where each pronunciation has the same or similar meaning. But to limit the scope of this question, I’m leaving out that topic here.)
Are there any articles/discussions about this sort of topic? Ideally they would be in English, and not be too scholarly. But maybe that's too much to hope for...!
I found a related question: Two-character homonyms with same meaning which is about variant spellings (异形词). This question is a little bit different I think. I'm interested in when the pair are considered to be two separate words, but whose meaning is the same (or almost the same).
Edit: I just came across another pair, 按 and 摁. They're not synonyms, but the meanings are still quite close.
Edit 2 (2018-04-03): This question is about pairs of words/terms (词) where the pronunciation is similar but different and the meaning is the same, or close. An attempt at saying it in Chinese: 同义或近义，音近但是不一样的词.
Here is another example: 直爽—直率. Also, I found two other candidates but I'm not sure if they qualify, as the difference in meanings may be a bit too much:
Edit 3 (2018-04-05): Just noticed another example (贫困—贫苦). I think it may be helpful to keep this question up to date with lists of all the examples I'm aware of.
Synonyms / 同义词：嫉妒—忌妒，嘟囔—嘟哝，贫困—贫苦，堵塞—阻塞
Similar (but distinct) meanings / 近义词：按—摁，直爽—直率，挣钱—赚钱