Does anyone use the 'tit do' construction anymore for 'falling into' as in for example 'thit sé dá chodladh'? I learned 'thit sé ina chodladh' in school and it does seem that form is used more often. What do you all use?

"Thit sé ina chodladh" would certainly float my boat.

But what about this one; "Thit sé le fáin" translating roughly as "He fell off a cliff" or "over an edge" or something. I'm not certain about this, so is there anyone out there who has come across this "thit" followed by "le" construction before? Maybe it's archaic but then again maybe it isn't.

le fána a thiteann duine neamhaireach!

Is iomaí slí le Titim, féach an bhFoclóir Beag:

titim amach (bruíon (le duine); tarlú (cad a thit amach?)).
titim ar (teacht anuas ar (is orm a thit an obair); teacht ar (níor this néal orm)).
titim cainte (leagan cainte, abairt).
titim chun (dul chun (ag titim chun feola, chun suaimhnis)).
titim focail (rith nó sciorradh focail).
titim i (ísliú ó staid go staid eile (titim i laige, i bpeaca)).
titim le (teacht chuig (is leat a thitfidh an áit)).

My kerry farmer father in law would refer to "a fall of ground" to describe a downward slope. Despite having very little Irish, his conversation is littered with words, usages, constructions etc which are heavily influenced by Irish. I wonder would "titim talún" be understood?

An bhfuil focal ann "titimeas", galar a bhaineann leis na néaróga a thugtar cerbral palsy no rud éicint cosúil leis air i mBéarla?

Tá. Epilepsy atá i gceist.