The second syllable of 'computer' contains a yod (or /y/); however, the second syllable of 'popular' doesn't contain a yod. Your 'newest' contains a yod; however, AmE doesn't have a yod after alveolar and dental consonants (l, r, s, z, d, t, n, th, voiced th, ch, dz) I don't hear a yod in the second syllable of "January": even though /n/ is alveolar, there is a yod, since /n/ is not part of that syllable.
2. Macintosh: the last syllable contains a COT vowel; in your version, I hear a monophthong OH.
3. "brand continues to * stay" I hear a sound like "the" before stay.
4. processing: I hear a /z/ in the second syllable.
5. MacOS: /s/ sound is not consistent. I hear both /z/ and /s/.
You got AmE lilt; so, you can pass off as a native speaker. You can work on "where to keep yod; where to drop y"--and this is a systematic phenomenon in AmE.
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