Não fales com a boca cheia, por favor.

Don't speak with your mouth full, please.

Breakdown of Não fales com a boca cheia, por favor.

• por favor: please
• com: with
• não: not
• falar: to speak
• cheio: full
• a boca: the mouth

Questions & Answers about Não fales com a boca cheia, por favor.

Why is it fales and not falas or fala?

In European Portuguese, negative commands use the present subjunctive. For tu, that’s fales. Compare:

• Affirmative commands: fala (tu), fale (você), falem (vocês)
• Negative commands: não fales (tu), não fale (você), não falem (vocês)

Falas is the present indicative (you speak), not used for commands.

Can I say Não fala in Portugal?

No, not in standard European Portuguese for addressing tu. You should say Não fales. In Brazil you may hear Não fala in some regions (especially with colloquial tu), but in Portugal that sounds incorrect.

How would I say this to someone formally or to more than one person?

• To one person politely/formally (você): Não fale com a boca cheia, por favor.
• To several people (vocês): Não falem com a boca cheia, por favor.

Where can I put por favor and do I need the comma?

You can place it at the end or the beginning:

• Não fales com a boca cheia, por favor.
• Por favor, não fales com a boca cheia. A comma is customary to set off por favor, but speaking-wise it’s just a slight pause.

Is com a boca cheia the most idiomatic, or is de boca cheia better?

Both are understood. In Portugal, de boca cheia (usually without the article) is very common and idiomatic: Não fales de boca cheia. Your sentence with com a boca cheia is also acceptable.

Why is it a boca and not a tua boca?

Portuguese typically uses the definite article with body parts when it’s clear whose body part it is. So a boca (the mouth) means “your mouth” here. A tua boca is possible but more emphatic or contrastive.

Why cheia and not cheio?

Agreement: boca is feminine singular, so the adjective must match: cheia (feminine) not cheio (masculine).

Should com a contract like de + a = da?

No. Com does not contract with the article: com a, com o. By contrast, de + a contracts to da, which is why with the idiomatic option you don’t usually use the article at all: de boca cheia (not da boca cheia in this expression).

How would I include an object pronoun, like “Don’t talk to me with your mouth full, please”?

In negative commands, pronouns go before the verb (proclisis):

• Não me fales de boca cheia, por favor. Compare the affirmative, where the pronoun attaches after the verb:
• Fala-me de boca cheia (unnatural content-wise, but shows placement).

Can I use dizer instead of falar?

You can, but it changes the nuance. Não digas de boca cheia targets “don’t say (that) with your mouth full,” more about a specific utterance. Não fales… is the usual general admonition “don’t talk…”.

Is the tone polite enough? Any softer alternatives?

With por favor, it’s polite but still direct. Softer options:

• Podes, por favor, não falar de boca cheia? (Could you please not talk with your mouth full?)
• Fala depois de engolires, por favor. (Speak after you swallow, please.)

How is the sentence pronounced in European Portuguese?

Approximate guide:

• Não: nasal “ow” sound
• Final -s in fales sounds like “sh”
• ch in cheia is “sh”; ei like “ay” → “SHAY-uh”
• r in por is a light tap Roughly: “nown FA-lish kong a BO-kah SHAY-uh por fah-VOR.”

Why does não have a tilde?

The tilde marks nasalization. Não is pronounced with a nasal vowel/diphthong (not like a plain “ao”).

Could I write this on a sign or rule list?

Yes, signs often use the infinitive or impersonal forms:

• Não falar de boca cheia.
• É proibido falar de boca cheia. For a polite notice: Por favor, não falar de boca cheia.