More like [ˈd̪ät̪ä], no long vowel. There’s also some disagreements if short /a/ was [ä] or [ɐ], given the symmetry with /e i o u/ as [ɛ ɪ ɔ ʊ]. (I can go deeper on this if anyone wants.)
Another thing that people don’t often realise, when they say “you should pronounce it like in Latin!”, is that Latin /d t/ were different from English/German /d t/. They were considerably less aspirated, and as your transcription shows they were dental.
That’s just details though. Your core point (Latin didn’t use a diphthong in this word) is 100% correct.
More like [ˈd̪ät̪ä], no long vowel. There’s also some disagreements if short /a/ was [ä] or [ɐ], given the symmetry with /e i o u/ as [ɛ ɪ ɔ ʊ]. (I can go deeper on this if anyone wants.)
Another thing that people don’t often realise, when they say “you should pronounce it like in Latin!”, is that Latin /d t/ were different from English/German /d t/. They were considerably less aspirated, and as your transcription shows they were dental.
That’s just details though. Your core point (Latin didn’t use a diphthong in this word) is 100% correct.