אם תדלגי על שתי מילים קשות, יהיה לך קשה להבין את התרגום כולו.

תדלגי is the 2nd-person feminine singular future form of לדלג (to skip).

So this sentence is addressed to one female:

• אם תדלגי... = if you skip...

If you were speaking to a male, it would be:

• אם תדלג...

If you were speaking to more than one person, the verb would change again.

Also, after אם (if), Hebrew often uses the future tense for a real future condition, even where English may use the present:

• אם תדלגי... יהיה...
  literally: if you will skip... it will be...
  natural English: if you skip... it will be...

Because לדלג usually takes the preposition על when it means to skip over something.

So:

• לדלג על מילה = to skip a word
• לדלג על שורה = to skip a line

Even though English just says skip something, Hebrew normally says skip over something with על.

When the number two comes directly before a noun, Hebrew uses the special construct form:

• שני
  • masculine noun
• שתי
  • feminine noun

Since מילה (word) is feminine, you get:

• שתי מילים = two words

Compare:

• שני ספרים = two books (masculine)
• שתי מילים = two words (feminine)

שתיים is the standalone form, not the form normally used directly before a noun.

The singular noun is מילה, and מילה is feminine. Its plural is מילים.

You can also tell from the agreement:

• שתי is feminine
• קשות is feminine plural

Both of those match מילים.

This is a good example of how Hebrew shows gender through agreement across the sentence.

Because in Hebrew, adjectives usually come after the noun they describe.

So:

• מילים קשות = difficult words literally: words difficult

The adjective must also agree with the noun in:

• gender
• number
• sometimes definiteness

Here:

• מילים = feminine plural
• so the adjective is קשות = feminine plural

Compare:

• מילה קשה = a difficult word
• מילים קשות = difficult words

לך means to you.

Hebrew often expresses this idea as:

• יהיה ל־... קשה + infinitive
• literally: it will be hard to... for someone
• natural English: it will be hard for someone to...

So:

• יהיה לך קשה להבין
  literally: it will be hard to-you to understand
  natural English: it will be hard for you to understand

This is a very common Hebrew pattern:

• קשה לי להבין = It is hard for me to understand
• יהיה לו קל לזכור = It will be easy for him to remember

Because this is an impersonal expression: יהיה לך קשה = it will be hard for you.

There is no explicit feminine subject here. Hebrew commonly uses יהיה in this kind of structure as a default singular form.

You can think of it as similar to English it will be hard. The it is not referring to a feminine noun, so there is no reason to use תהיה.

Because קשה + infinitive is one of the most natural and common ways in Hebrew to say it is hard to...

So:

• יהיה לך קשה להבין = it will be hard for you to understand

Hebrew could express a similar idea in other ways, but this pattern is very standard and idiomatic.

It is worth learning as a chunk:

• קשה לי לעשות את זה = It is hard for me to do this
• היה להם קשה לשמוע = It was hard for them to hear

Because after קשה (hard/difficult), Hebrew often uses an infinitive to say hard to do something.

So:

• קשה להבין = hard to understand
• קל לקרוא = easy to read
• חשוב לדעת = important to know

Here:

• יהיה לך קשה להבין = it will be hard for you to understand

So להבין is not tied to a separate subject ending; the subject is already understood from לך.

את is the direct object marker. It appears before a definite direct object.

Here, התרגום means the translation, and it is definite because of ה־ (the). So Hebrew puts את before it:

• להבין את התרגום = to understand the translation

Important:

• את here does not mean you
• it is just a grammatical marker

Compare:

• אני קורא ספר = I am reading a book
• אני קורא את הספר = I am reading the book

כולו means all of it or the whole of it.

So:

• התרגום כולו = the entire translation / the whole translation

It is built from כל (all) plus a suffix referring back to the noun:

• כולו = all of it for a masculine singular noun

Since תרגום is masculine singular, כולו matches it.

Compare:

• הספר כולו = the whole book
• הכתבה כולה = the whole article

This structure often sounds a bit more emphatic or formal than just כל התרגום, though both can express the whole translation.

Both are possible, but they are slightly different in feel.

• כל התרגום = all the translation / the whole translation
• התרגום כולו = the translation in its entirety / the whole translation

התרגום כולו often sounds a bit more complete or emphatic, as if stressing the entire thing.

For a learner, the important point is that כולו agrees with תרגום:

• masculine singular noun → כולו
• feminine singular noun → כולה

Yes, very normal.

The sentence is built like this:

• אם תדלגי על שתי מילים קשות = if you skip two difficult words
• יהיה לך קשה = it will be hard for you
• להבין את התרגום כולו = to understand the whole translation

This order is very natural in Hebrew. In particular, the pattern:

• יהיה לך קשה + infinitive

is something you will see often.

Not exactly as written.

As written, תדלגי shows the speaker is addressing one female. If the speaker were addressing one male, the sentence would be:

• אם תדלג על שתי מילים קשות, יהיה לך קשה להבין את התרגום כולו.

Notice that לך stays the same in writing for both masculine and feminine singular. The main visible change here is:

• תדלגי → תדלג