agi- - "I", this is a "B" Class bound pronoun, used before a consonant.
-wonihis- - infinitive verb stem for "speak"
-di - infinitive suffix. All infinitive forms use "B" class bound pronouns and usually have a different verb stem.
In Cherokee, an infinitive must have a bound pronoun; agi-wonihis-di (for me to speak), tsa-gowadv-di (you - to see it).