In IPA, [mɛːɹɪj], [mɛɹɪj], [maɹɪj] is what I say. Basically Mary has a long “eh” sound, merry has a short “eh” sound and marry has a short “ah” sound (you can check the IPA vowel chart for the specific sounds here) In General American I think speakers without the merger say them something like [mɛɚ.ɪj], [mɛɹɪj], [mæɹɪj], although over half of Americans are supposed to have the merger now.
How… how do the rest of you pronounce them?
In IPA, [mɛːɹɪj], [mɛɹɪj], [maɹɪj] is what I say. Basically Mary has a long “eh” sound, merry has a short “eh” sound and marry has a short “ah” sound (you can check the IPA vowel chart for the specific sounds here) In General American I think speakers without the merger say them something like [mɛɚ.ɪj], [mɛɹɪj], [mæɹɪj], although over half of Americans are supposed to have the merger now.
If you’re interested, you can read more here