I know that the words there, their, and they're are homophones
Yes.
but I can't help but think that their has a slight /j/ between /e/ and /r/ (/ðer/).
It’s possible, but no more so than for there and they’re. I don’t think you’re imagining things, but I also wouldn’t recommend taking any special efforts to pronounce this word this way.
For American English speakers, there is generally no phonemic contrast between the vowel in there/their/they’re and the vowel in they/say/fade/male/mail. (This holds regardless of whether we’re talking about an accent with or without the Mary-marry-merry merger.)
But phonetically, you’re less likely to hear a /j/-like glide when the vowel is followed by /r/ with no intervening word boundary, and more likely to hear a glide when the vowel is word-final, followed by a vowel, or followed by most other consonants, like /p b m t d n k g s z f v θ ð tʃ dʒ/. For me, the /j/-like off glide of the vowel /e/ is also suppressed to some extent before a following /l/ (which I pronounce as “dark l”, [ɫ]), but I don’t know how common this is or the details of how it works (I do distinguish pairs like fail and fell).
Answer from herisson on Stack ExchangeSomebody told me today that these two are homophones. You must be kidding me. I consider myself pretty well-versed in many varieties of English, but would never consider them homophones. Is "ei" in "their" really not pronounced as /eɪ/ (like ate, fame), but just as flat /ɛ/?
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I'm from Victoria, Australia, and I've noticed that no-one I know and no-one I've ever heard does this except me, most of my friends can't even hear the difference.
I don't know how to write this phonetically but the difference is, as well as I can describe it, like the difference between 'air' and 'aya' only less distinct than 'aya' would be.
EDIT: While recording I may have modified it by thinking about it too hard, but I think this is close to how I would say the two in conversation (as I don't distinguish between 'their' and 'there').
EDIT: I posted this question because I couldn't find anything on it using Google, is there a name for this or is it a relatively unknown phenomenon (the pronunciation of these words not as homophones)?
Question to the natives: is there any difference between either of the three? Also, if you do distinguish them, it would be interesting for me to know what accent you have. I've almost convinced myself that I can sometimes hear the /j/ sound in "they're" in some accents. Am I tripping?