Parler means to talk
The verb 'parlez' means you all speak, you all talk. The verb is in the second person plural ['vous'] of the present indicative tense. The second person singular is 'tu parles'.
(vous) parlez means (you) speak in French.
The statement 'Parlez en francais' means Speak in French. In the word-by-word translation, the verb 'parlez' means '[you] speak'. The preposition 'en' means 'in'. The noun 'francais' means 'French'.
The question 'Est-ce que vous parlez Francais' means Do you speak French. In the word-by-word translation, the verb 'est' means '[he/she/it] is'. The demonstrative pronoun 'ce' means 'this'. The conjunction 'que' means 'that'. The personal pronoun 'vous' means 'you'. The verb 'parlez' means '[you] speak'. The noun 'Francais' means 'French'.
The sentence 'Alors vous parlez francais' means So you speak French. In the word-by-word translation, the adverb 'alors' means 'in that case, so'. The personal pronoun 'vous' means 'you'. The verb 'parlez' means '[you] speak'. And the noun 'francais' means 'French'.
Parlez-vous français? in French is "Do you speak French?" in English.
parlez-vous français means 'do you speak French' in French.
do you speak French well is translated "parlez-vous bien français / est-ce que vous parlez bien français" in French
"Can you speak English?" translates to "Parlez-vous anglais?" in French.
parlez-vous français ? means "do you speak french?"
Parlez-vous inglés? in mixed French (Parlez-vous [anglais]?) and Spanish ([¿Habla usted] inglés?) means "Do you speak English?" in English.
The statement 'Parlez en francais' means Speak in French. In the word-by-word translation, the verb 'parlez' means '[you] speak'. The preposition 'en' means 'in'. The noun 'francais' means 'French'.