I understand you!

Tha mi gad thuigsinn! 

This is a useful phrase to know, just as useful as chan eil mi gad thuigsinn . Let's start with the question. 

A bheil thu  gam thuigsinn?  Do you understand me? 
A bheil i  gad thuigsinn?  Does she understand you? (singular) 
A bheil thu  ga thuigsinn?  Do you understand him? 
A bheil thu  ga tuigsinn?  Do you understand her? 
A bheil thu  gar tuigsinn?  Do you understand us? 
A bheil i  gur tuigsinn?  Does she understand you? (formal/polite/plural) 
A bheil thu  gan tuigsinn?  Do you understand them? 
Tha thu  gam thuigsinn.  You understand me 
Tha i  gad thuigsinn.  She understands you. (singular) 
Tha thu  ga thuigsinn.  You understand him. 
Tha thu  ga tuigsinn.  You understand her. 
Tha thu  gar tuigsinn.  You understand us. 
Tha i  gur tuigsinn.  She understands you. (formal/polite/plural) 
Tha thu  gan tuigsinn.  You understand them. 

You'll remember we learnt about dè cho tric …? in the previous section. We can use this in a similar way. 

Dè cho tric 's a bhios tu a' faicinn do sheanmhair?
How often do you see your granny?
Dè cho tric 's a bhios tu ga faicinn?
How often do you see her?
Dè cho tric 's a bhios tu a' faicinn do sheanair?
How often do you see your grampa?
Dè cho tric 's a bhios tu ga fhaicinn?
How often do you see him?

And note: 

ga fhaicinn
seeing him
ga faicinn
seeing her