Asking Chinese mother-in-law to learn pinyin? I thought about asking this on parenting.se but it seemed specialized enough that this site made more sense.

I'm a white man married to a Chinese woman, living in the US. Her parents live in China and are retired (they're about 65yo), and my wife is an only child. Her mother has come over to stay with us twice for long periods to be with and help take care of our son (currently 3yo). She has been immensely helpful both times. Both her parents only speak Mandarin and their regional dialect.

Although there are some (ahem) advantages to not being able to communicate with my in-laws, I've spent considerable time trying to learn Mandarin. It's been frustrating: sometimes I should be able to understand something she's saying (i.e. I know the vocabulary) but can't because her regional accent makes some sounds different from standard. E.g. 'n' and 'l' are the same in her dialect. She can't hear or pronounce the difference between 'snow' and 'slow'. This goes both ways: my pronunciation often isn't good enough for her to distinguish what I'm saying... even though when she finally does get it and repeats it for me, it sounds exactly the same to me (ugh!). So when my wife isn't around (or just as often, gets tired of acting as translator) it would be nice for either of us to be able to write out what we're saying, phonetically.

My mother-in-law's generation didn't learn pinyin. To me it seems fairly easy to learn but that's probably because the Latin alphabet is second-nature to me as a native English speaker. She can associate Chinese characters with phonemes of course, but not with Latin letters (although she can actually identify and say all the letters in the English alphabet).

I've asked my wife about teaching her mom pinyin, but my wife was dismissive and annoyed at the suggestion: usually something like "they're too old to learn". So before I ask my mother-in-law myself if she's interested in learning pinyin so we can communicate better, I wanted to get advice from strangers on the internet. Is it reasonable to try to get her to learn pinyin? Anybody else been in a similar situation?
If your mother-in-law confuses n and l, it's unlikely that knowing pinyin would be enough for her distinguish those words like in standard Chinese. Just because she knows what an n or l is doesn't mean that she'll know which words are supposed to begin with what consonant. If you want her to distinguish n/l in her speech (not sure from your question whether you are), you're not just teaching her pinyin; you'd have to teach her the pinyin of all the n/l words, and then have her speak it that way.

For instance, my parents merge s/sh, z/zh, c/ch, and n/ng. They know pinyin, and they know they confuse those sounds, but they don't necessarily know how those words are supposed to be spelled.  Plus, I've told my mom that 弄 (nòng) should not be pronounced lòng, but she does it anyway, even though she distinguishes n/l in almost all other circumstances. Old habits die hard.

For an another analogy, let's say you are a speaker of American English and have a British friend who can't understand it when all those pesky Americans who keep pronouncing "caught" like "cot". Would you really know whether "not", "naught", or "nought" is the one with the /ɑː/ or the /ɔː/?



If you want to understand her better, I'd recommend just getting used to the n/l merger or whatever idiosyncratic pronunciation your mother-in-law uses. When she says n, consider if it could've been an l word, and vice versa. Have her write out the characters on a piece of paper instead of in the air. Perhaps even just have her dictate into Google Translate or Bing Translator.

As for how she can understand you better, consider pulling out your phone and using an IME instead of writing out the pinyin. Even if she learns pinyin, it's probably going to be a lot slower for her to read it than hanzi. When I was first learning hangeul, it took me a few months to get comfortable enough to not mix up some letters. Something with haphazardly designed letters like Latin, and something with quirky spelling conventions like pinyin, are probably going to be pretty hard to read for an elderly person. With regional dialects, she might be getting the tones or other phonemes of the word wrong too, so she might have trouble decoding what you wrote.

Also, maybe ask your wife why she thinks her mother has trouble understanding you. Are you subtly mispronouncing the words somehow (maybe in terms of tone), or does your mother only understand a certain nonstandard pronunciation?