No tragues tan rápido; prueba primero un bocado más pequeño.

Because negative tú commands in Spanish use the present subjunctive.

The verb is tragar. Its present subjunctive forms are:

• trague
• tragues
• trague
• traguemos
• traguéis
• traguen

So the negative command to one person is:

• No tragues

Also, -gar verbs change g → gu before e in forms like this, so the hard g sound stays the same.

Compare:

• traga = affirmative tú command
• no tragues = negative tú command

Because this is an affirmative tú command, and affirmative tú commands normally use the same form as the 3rd person singular present indicative.

The verb is probar:

• él/ella/usted prueba
• therefore the affirmative tú command is prueba

So:

• Prueba = try
• No pruebes = don’t try

This is a very common pattern:

• come / no comas
• habla / no hables
• prueba / no pruebes

Because Spanish treats affirmative and negative informal commands differently.

For tú:

• affirmative command → imperative form
  
  • prueba
• negative command → present subjunctive
  
  • no tragues

So in the same sentence, it is perfectly normal to have:

• No tragues...
• prueba...

That difference is a basic rule of Spanish commands.

Tan means so and muy means very.

Here, tan rápido means something like so fast / that fast, which sounds natural when telling someone to slow down. It suggests the speed is excessive in the situation.

• No tragues tan rápido = don’t swallow so fast
• No tragues muy rápido = don’t swallow very fast

The second one is grammatically possible, but tan rápido is more natural for this kind of warning or correction.

In everyday Spanish, especially with common verbs, an adjective like rápido is often used adverbially to mean quickly/fast.

So both are possible:

• No tragues tan rápido
• No tragues tan rápidamente

But rápido is much more natural and common in ordinary speech.
Rápidamente sounds more formal or heavier.

This happens a lot in Spanish:

• habla claro
• ve directo
• come rápido

Here primero means first, and it works as an adverb, not as an adjective.

It tells you the order of actions:

1. first, try a smaller bite
2. then presumably continue eating

Because it is an adverb here, it stays primero and does not agree with bocado.

So:

• prueba primero un bocado más pequeño = first try a smaller bite

It could also appear in a different position:

• prueba un bocado más pequeño primero

But the original order sounds very natural.

Because in Spanish, adjectives usually come after the noun.

So:

• un bocado pequeño = a small bite
• un bocado más pequeño = a smaller bite

Putting the adjective before the noun is much less common and often changes the tone or emphasis. In ordinary speech, bocado más pequeño is the normal order.

Bocado means a bite or mouthful of food.

In this sentence, it refers to the amount of food someone puts in their mouth at one time. So un bocado más pequeño means a smaller amount of food in one bite.

It is a very natural word in this context because the sentence is about eating too fast and taking a smaller bite.

Because más pequeño is the most natural everyday way to talk about physical size here.

• un bocado más pequeño = a smaller bite

Menor does exist and can mean smaller/lesser, but it often sounds more formal, abstract, or is used in other contexts, such as:

• de menor importancia
• un menor de edad

For food and size in normal conversation, más pequeño is the better choice.

Because Spanish usually omits subject pronouns when the verb form already shows who the subject is.

Both verbs clearly point to tú:

• no tragues
• prueba

So adding tú is unnecessary unless you want emphasis, contrast, or a stronger tone.

For example:

• Tú no tragues tan rápido...

This sounds more emphatic, like you are specifically singling that person out.

Not exactly.

• comer = to eat
• tragar = to swallow, gulp down

So tragar focuses more on the act of swallowing, especially swallowing too quickly or without enough care. That makes it a good choice here.

If you said:

• No comas tan rápido

that would also be natural, but it means more generally don’t eat so fast.

No tragues tan rápido is a bit more specific and vivid.

In Spain, for an informal plural command, you would usually use vosotros forms.

So the sentence would become:

• No traguéis tan rápido; probad primero un bocado más pequeño.

Changes:

• no tragues → no traguéis
• prueba → probad

This is especially useful in Peninsular Spanish, since vosotros is very common there.

The semicolon links two closely related instructions:

• don’t swallow so fast
• try a smaller bite first

A semicolon shows that the two parts are separate but strongly connected. It is a punctuation choice, not a grammar requirement.

You could also see:

• No tragues tan rápido. Prueba primero un bocado más pequeño.
• No tragues tan rápido, prueba primero un bocado más pequeño.

But the semicolon is neat and clear, especially in written Spanish.