Why would "Cá bhfuil do chuid inneall?" be considered wrong?
Because do chuid inneall would be a translation of “your engines”.
Because "do chuid" indicates "your share", m.sh, do chuid gruaige, do chuid airgid, do chuid oibre srl
Whats wrong with Cá bhfuil do inneall.
when mo and do come before a word that starts with a vowel sound, the become m' and d' - it's not optional.
It's a "vowel sound", not just a vowel, because words that start with f, which is silent when lenited are also effected: m'fhón - "my phone".
It is grammatically incorrect because of the vowels, I believe. There's a fairly detailed explanation earlier on in the possessive lessons.
Why is this inneal, when my prior question said meaisín meant engine?
Meaisín = machine. Inneall = engine.
"inneall fuála" - "sewing machine"