I may be crazy but I feel the ghostly presence of the “b”. For instance say “let let let let det” Now say “let let let let debt” Train a neural net on a few million samples of native English speakers reading these, and I think it could predict which prompt was read with >50% accuracy, even if each person was only shown one of the prompts.
It's very interesting people think so, and I've heard similar statements about the in "scent". Yet linguistically, it really doesn't hold up. Words are built up from phonemes, which undergo some alterations depending on their order and the context to become the phones (as in sounds, not telephones) which are actually pronounced. But this allophonic variation is never dependent on the spelling of the word†, and the wo…
If you ask them about it most of them think they are saying the vowel because in their mind, since they've been taught that way their entire life, there is always a vowel. But record them and process the phonemes out and they are dropping it 99% of the time.
The most common examples are "desu" and "suki". You can find examples of people saying "de-su" and "su-ki" but most of the time they just say "des" and "ski".
It's a problem for foreign language students because the teacher will tell them it's "de-su" and "su-ki" and then the student will say "de-su" and "su-ki" and not sound remotely like a native.