Shouldn't be a space after the apostrophe, should be a'
I believe "is she understanding" relates to understanding the words being said - i.e. in a language sense. But does "a' tuigsinn" also apply in a "compassionate" meaning?
It comes from «tuig» which relates to reasoning and knowledge:
tuig (vb) /tɯgʲ/
v. n. -sinn
2 comprehend understand
«Tha co-fhaireachdainn agam riut» ≈ "I have fellow feeling with you" comes close to 'compassion'.
This phrase has long been used by native speakers in a compassionate sense. My understanding of it in the sense of knowledge or reasoning would be confined largely to classroom /teaching situations.