As in English, the verbs in French are always accompanied by a personal pronoun, and it’s the pronoun that identifies the person (1st, 2nd and 3rd person, singular or plural).
French is not written as it is pronounced, nor is it pronounced as it is written; most final consonants are silent.
For example, the verb tu téléphones (you telephone) is pronounced as in je téléphone. It is therefore the pronoun that identifies the person.
Further explanations are available in the A1 grammar sheets: “Les pronoms personnels”, “Le présent des verbes du 1er groupe”, “Le présent des verbes du 2ème groupe” and “Le présent des verbes du 3ème groupe”.