I know that words like
cuppa, fella, attaboy and attagirl
are contractions of, respectively,
cup of tea, fellow, that's the/a boy and that's the/a girl.
I wonder if there is a term which would describe the process through which the orthography of these contracted words changed to what they call phonemic orthography (writing words as they are pronounced).
For example, the British cuppa comes from cup of tea but it renders just cup of.
As for attaboy, it comes from that's the boy, but there were stages ("That's the boy"—"'at's a boy"—"atta boy" – there is even a variant of at her, boy!)
Also, cuz just popped into my mind because (!) it became so short. Kinda seems to be kind of (!) in between.
So from a proper English orthography there is a shift towards phonemic orthography in informal English. Is there a term for this? Does anyone know of any reliable investigations of this process?
Edit: The question indicated as already existing does shed some light, but the accepted answer is relaxed pronunciation. And the question seems to focus on speech and pronunciation. My question is rather about this tendency to write in this way in informal writing. It may be though that such term does not exist in orthography. The result is phonemic orthography; just wondered if the process leading to it has a name.