This is the 274th most frequent Italian word.
parla
"Parla" means "he/she speaks" or "you speak" (formal) in English.
Here, 'parla' is the third person singular present tense of 'parlare', used to indicate a habitual action performed by 'lei' (she).
Lei parla italiano fluentemente.
She speaks Italian fluently.
In this sentence, 'parla' again is the third person singular present tense of 'parlare', describing an action done by 'lui' (he) in a specific way.
Mi piace quando lui parla piano.
I like it when he speaks slowly.
Here, 'parla' is used in a present general statement showing an action performed typically and universally during class sessions.