Best to incorporate from the beginning of the introduction of the alphabet unit, but never too late either.
When introducing or teaching the alphabet and their pronunciations, do so with their phonetic counterpart.
For example: /a/, /a/, A; /b/, /b/, B... and so on.
This is so when you play bingo, you use the same pattern.
Students: What letter?
ALT: /t/, /t/, T!
Students: [repeat and circle the letter]
ALT: [reveals the letter to confirm]
The 'level up' challenge is to make the phonic sound only.
Students: What letter?
ALT: /t/, /t/...
Students: T!
ALT: That's right! [reveals the letter to confirm]
and so on.
This is a great way to quickly correct and reinforce letter-phonic association. And since all the students are calling out the phonics together, no student in particular is singled out, and they get to learn from their peers.
I tried this today (Nov. 29th, 2024) in 4 of 5 classes I had with Grade 3 elementary students, and they were really quick to pick up. I was also able to recorrect and reinforce more difficult sounds like /b/, /v/, /m/, /n/ and other pairs that the Japanese pronunciation makes difficult to differentiate.
Very easy to do and applicable to any grade learning the alphabet, or re-encountering it in 1st year JHS.