@richieuk87
Verbs are really tricky in Tagalog...takes some getting used to!
The first example is not quite correct...It should be "Kinausap ko siya kanina" = "I talked to him/her earlier" to get the focus right.
"Nag-usap" would be used in a different way. (nag-usap is actor focused, and the actor is always plural for the nag-usap form..see the dictionary entry for this verb on this website for some example sentences).
You are right about the abilitive form in the second example, but you also use that form to say something along the lines of "I haven't had a chance to speak to her..." if you had said "Hindi ko siya kinausap," it would almost feel like you were purposely choosing not to talk to him/her, which is probably not the tone you're going for.