The distinction between dependent and independent is an established concept in linguistics in general, and functions at a clausal level. The only wrinkle in Gaelic is the reanalysis of copular constructions as pre-verbal particles. That's not a major wrinkle though, as the same logic holds -- the verb's meaning is dependent on what preceded it.
It manifests itself in the particles in front of the verb. The distinction in meaning is why we use the particle.It merely boils down to what particle sits in front of the verb. In Gaelic, that boils down to 3 options:
I mean we wouldn't say the main distinction between "duck" and "goose" is the word -- the real difference is the meaning of what the words refer to.