T and Y changing to CH sound
This may be a terribly stupid question, but what is the process called whereby t-sounds followed by y-sounds, and other similar consonants, change to a ch-sound? E.g., what you changing to whatchu.
I knew it a couple of months ago, but of course now I need it, I can't remember.
To make up for that, here's a more interesting one:
1. Jack likes him.
2. He likes Jack.
3. Jack says he likes Mary.
4. He says Jack likes Mary.
Why is it that in sentence #3, the pronoun is ambiguous, but in the others, it must be a different person from Jack?
I knew it a couple of months ago, but of course now I need it, I can't remember.
To make up for that, here's a more interesting one:
1. Jack likes him.
2. He likes Jack.
3. Jack says he likes Mary.
4. He says Jack likes Mary.
Why is it that in sentence #3, the pronoun is ambiguous, but in the others, it must be a different person from Jack?