La pulga salta muy alto.

In Spanish, it is very common to use the definite article (el, la, los, las) where English might simply say the or sometimes even leave it out in other contexts.

Here, la pulga means the flea.

• la = the for a singular feminine noun
• pulga = flea

So la pulga salta muy alto is literally the flea jumps very high.

You could also say una pulga if you mean a flea instead of the flea.

Because the noun pulga is feminine in Spanish, so it takes la.

There is no perfect rule that always tells you a noun’s gender, but many nouns ending in -a are feminine, and pulga is one of them.

So:

• la pulga = the flea
• una pulga = a flea

Remember that grammatical gender in Spanish does not always match biological sex. A flea is not being described as biologically female here; pulga is just a feminine noun.

Salta is the third-person singular present tense form of the verb saltar, which means to jump.

Conjugation of saltar in the present:

• yo salto = I jump
• tú saltas = you jump
• él/ella/usted salta = he/she/you jump(s)

So in La pulga salta, salta means jumps.

Spanish often leaves out subject pronouns because the verb ending already tells you who the subject is.

In this sentence, the subject is explicitly stated as la pulga, so there is no need to add ella.

• La pulga salta = The flea jumps
• Ella salta = She jumps

Using ella here would usually be unnecessary unless you wanted emphasis or contrast.

Use muy before adjectives and adverbs to mean very.

Here, alto is functioning adverbially, describing how the flea jumps, so muy is correct:

• muy alto = very high

Mucho usually means much/a lot/many and is used differently.

Compare:

• salta muy alto = jumps very high
• salta mucho = jumps a lot

So muy is the right word in this sentence.

Great question. Here, alto is not describing the noun pulga. It is describing the verb salta—in other words, it tells you how the flea jumps.

So alto here works like an adverbial expression meaning high, not like a normal adjective agreeing with pulga.

• La pulga es alta = The flea is tall/high-sized.
  Here alta describes the flea, so it agrees with pulga.
• La pulga salta alto = The flea jumps high.
  Here alto describes the action, so it stays alto.

That is why you do not say muy alta in this sentence.

In this sentence, alto is being used in an adverbial way.

Normally, alto/alta is an adjective meaning tall or high:

• un muro alto = a high wall
• una mujer alta = a tall woman

But after certain verbs, especially verbs of movement or position, Spanish often uses an adjective-like form to express something that English would usually express with an adverb:

• hablar claro = to speak clearly
• volar bajo = to fly low
• saltar alto = to jump high

So in La pulga salta muy alto, alto means high, modifying the action.

Yes, Spanish word order is somewhat flexible, but the normal, neutral order here is:

• La pulga salta muy alto.

You might also hear:

• Muy alto salta la pulga.

That sounds more literary, emphatic, or marked, like Very high the flea jumps.

For a learner, the standard order subject + verb + adverbial phrase is the best one to use.

In most Latin American Spanish, muy is pronounced approximately like mwee.

A simple breakdown:

• m as in English man
• uy forms one syllable, sounding like wee with a slight glide at the start

So:

• muy ≈ mwee

It is one syllable.

The natural stress is:

• la PUL-ga
• SAL-ta
• muy
• AL-to

So the whole sentence sounds roughly like:

la PUL-ga SAL-ta muy AL-to

Spanish stress is very regular, and none of these words has a written accent mark because they already follow normal stress rules.

Yes, in many parts of Latin America, brincar can also mean to jump.

So both of these can work:

• La pulga salta muy alto.
• La pulga brinca muy alto.

However, saltar is more universally understood across the Spanish-speaking world, so it is often the safer choice for learners.

Here it means high.

In Spanish, alto can mean different things depending on context:

• una persona alta = a tall person
• una montaña alta = a high/tall mountain
• saltar alto = to jump high

Since the verb is saltar, the meaning is clearly high, not tall.