The mutations in the Welsh language were originated from elements that came before words and affected them etc.
How does the fact that a certain noun is the direct object of a sentence trigger a soft mutation?
Gwelais i geffyl. (I saw a horse)
Geffyl being the soft mutation of ceffyl.
Was there an object marked lost in time that existed in proto-celtic? Maybe the verb's inflection itself caused it? Or is there a different explanation (or no explanation at all)?