Does "dochtúir" refer to only medical doctors or could it refer to PhDs etc. as well?
Yes, it can refer to Ph.D.s
Go raibh mile maith agat!
If you wish to be more specific, you can say medical doctor as in the Irish Medical Council's name (lit. Council of Medical Doctors): Comhairle na nDochtúirí Leighis. Leighis is the genitive of leigheas, which is medicine.
then best keep that doctor away from that student
Mac léine ?
mac léinn was the only phrase I knew of for "student". Does dalta have exactly the same meaning, the same way you can describe someone in English either as being "a student" or "a pupil"?
The meanings of dalta can be found here; they go beyond “student” and “pupil”.
My Irish teacher refers to us a mac léinn in e-mails. Dia dhaoibh, a mhaca léinn, a chairde, ...
Right, i thought mic leinn was student, áras na mhic léinn
The plural of mac léinn is mic léinn.
An doctúir agus a chompánach.
I gconai an dalta.
Taim an dalta i gconai
Probably more accurate.....