אם את מקלידה מהר מדי, את לפעמים לוחצת על המקש הלא נכון.

Because the sentence is addressed to a female singular you.

In Hebrew, present-tense verbs agree with gender and number, so:

• את = you (to one female)
• אתה = you (to one male)

That is why the verbs are also in feminine singular forms:

• מקלידה
• לוחצת

If you were speaking to a man, the sentence would be: אם אתה מקליד מהר מדי, אתה לפעמים לוחץ על המקש הלא נכון.

אם means if.

It introduces a condition:

• אם את מקלידה מהר מדי = If you type too fast

This is a very common Hebrew word for conditional sentences.

Hebrew often uses the present tense for general or habitual situations, just like English does in sentences such as If you type too fast, you sometimes press the wrong key.

So:

• את מקלידה = you type / you are typing
• In this sentence, it means a general habit or repeated situation, not just one action happening right now.

מקלידה comes from the verb להקליד, which means to type.

It is related to קליד, an older/formal word connected with typing or a keyboard key. In modern everyday Hebrew, להקליד is the standard verb for to type.

Forms:

• אני מקלידה / מקליד = I type
• את מקלידה = you (f.s.) type
• היא מקלידה = she types

מהר מדי means too fast.

The two parts are:

• מהר = fast / quickly
• מדי = too, excessively

Together they mean:

• מהר מדי = too quickly / too fast

You will often see מדי after an adjective or adverb:

• יקר מדי = too expensive
• קשה מדי = too difficult
• לאט מדי = too slowly

Hebrew often repeats the subject pronoun for clarity, especially when moving into a new clause.

So:

• אם את מקלידה מהר מדי, את לפעמים לוחצת...

Literally, this is something like:

• If you type too fast, you sometimes press...

In English, we also usually repeat you in this kind of sentence, so it feels natural in both languages.

לפעמים means sometimes.

In this sentence:

• את לפעמים לוחצת = you sometimes press

Its position is flexible, but this placement is very natural. You may also hear:

• לפעמים את לוחצת...
• את לוחצת לפעמים...

The version in your sentence sounds smooth and standard.

לוחצת comes from the verb ללחוץ, which means to press.

Here it is the feminine singular present form:

• לוחצת = you press / she presses (feminine singular)

Other forms:

• לוחץ = masculine singular
• לוחצים = masculine plural / mixed plural
• לוחצות = feminine plural

In the context of a keyboard, ללחוץ על מקש means to press a key.

Because the verb ללחוץ is commonly used with על when you press something physically.

So:

• ללחוץ על כפתור = to press a button
• ללחוץ על המקש = to press the key

This is just the normal Hebrew pattern for this verb in many contexts.

מקש means a key on a keyboard or keypad.

So:

• מקש = keyboard key / button-like key

It is not the same as:

• מפתח = a physical key used to open a lock

So in this sentence, מקש is exactly the right word because we are talking about typing.

Because Hebrew often uses the definite form when English uses the in a phrase like the wrong key.

Here:

• המקש = the key
• הלא נכון = the not-correct one = the wrong one

So:

• המקש הלא נכון = the wrong key

The adjective phrase also becomes definite because the noun is definite.

Compare:

• מקש לא נכון = an incorrect key / a wrong key
• המקש הלא נכון = the wrong key

Literally, לא נכון means not correct.

In Hebrew, this is a very common way to express wrong in many situations.

Examples:

• התשובה לא נכונה = the answer is wrong
• המספר לא נכון = the number is wrong
• המקש הלא נכון = the wrong key

In this sentence, it sounds completely natural.

Because the whole adjective phrase is definite, matching the definite noun המקש.

Hebrew adjectives agree with the noun in:

• gender
• number
• definiteness

So after a definite noun, the adjective phrase is also marked as definite:

• מקש נכון = a correct key
• המקש הנכון = the correct key
• המקש הלא נכון = the incorrect / wrong key

The ה attaches to the adjective phrase after the negative element, giving the standard form הלא נכון.

Yes, Hebrew has other ways to express the idea, but your sentence is very natural and straightforward.

For example:

• את לפעמים לוחצת על המקש הלא נכון = you sometimes press the wrong key
• את לפעמים טועה ולוחצת על המקש הלא נכון = you sometimes make a mistake and press the wrong key

But לוחצת על המקש הלא נכון is the clearest and most direct way to say it.

It describes a general tendency or repeated situation.

That comes from:

• the present tense
• the use of לפעמים = sometimes
• the if clause expressing a general condition

So the meaning is something like:

• Whenever you type too fast, you sometimes press the wrong key.

Here are the main versions:

To one man: אם אתה מקליד מהר מדי, אתה לפעמים לוחץ על המקש הלא נכון.

To one woman: אם את מקלידה מהר מדי, את לפעמים לוחצת על המקש הלא נכון.

To a group of men / mixed group: אם אתם מקלידים מהר מדי, אתם לפעמים לוחצים על המקש הלא נכון.

To a group of women: אם אתן מקלידות מהר מדי, אתן לפעמים לוחצות על המקש הלא נכון.

This is a good example of how Hebrew changes pronouns and present-tense verb forms to match gender and number.