Learn Spanish (Latin America): Sean claros, abogados.

Sean is the plural command form of the verb ser (to be). You use it when giving an order or advice to a group of people, corresponding to ustedes (you all). The verb ser is irregular for commands, so you just have to memorize that its ustedes form is sean.

Why do we use sean (from ser) instead of estén (from estar) to say 'be clear'?

We use ser with the adjective claro to describe someone who is easy to understand, direct, or straightforward. Since the speaker is telling the lawyers to make their speech clear, it is treated as a core characteristic of their communication, which requires ser.

Why does the word claros end in -os instead of -o?

Adjectives in Spanish must match the people or things they describe in gender and number. Because the speaker is talking to multiple lawyers (abogados, which is masculine plural), the adjective must also be the masculine plural form, claros.

Do I need to include the word ustedes in this command?