Если ты когда-либо сталкивалась с такой задержкой, скажи, что обычно помогает.

Because Russian past tense agrees with the gender and number of the subject, even with ты.

So:

• ты сталкивался = if you are speaking to a man
• ты сталкивалась = if you are speaking to a woman
• вы сталкивались = if you are speaking politely or to more than one person

The ending -ась here shows:

• past tense
• feminine singular
• reflexive verb

Russian does not have a separate present perfect tense like English have encountered. It usually uses the past tense instead.

So когда-либо сталкивалась naturally covers the idea of:

• have ever encountered
• ever ran into
• at some point experienced

This is very normal in Russian.

Because сталкиваться с is the imperfective verb, and it is often used for:

• general experience
• repeated situations
• the idea of ever having had something happen

Here the sentence means something like if you have ever had experience with this kind of delay.

By contrast, столкнулась would sound more like one specific completed event:

• Если ты столкнулась с такой задержкой... = if you happened to encounter such a delay in a particular case

So the imperfective fits better for broad life experience.

Когда-либо means ever, at any time, or at some point.

It is a fairly neutral or slightly formal way to express ever.

In this sentence:

• Если ты когда-либо сталкивалась... = If you have ever encountered...

A very common conversational alternative is когда-нибудь. In many everyday contexts, both can work, but когда-либо sounds a bit more precise or written.

Because the verb pattern is:

• сталкиваться с чем? = to encounter / come up against what?

The preposition с here requires the instrumental case.

So:

• dictionary form: такая задержка
• after с: с такой задержкой

Both words change:

• такая → такой
• задержка → задержкой

That is the reflexive marker.

The full reflexive ending is either:

• -ся
• -сь

They are just variant forms. After a vowel, -сь is common, so:

• сталкивалась
• училась
• боялась

The base verb is сталкиваться. In this expression, сталкиваться с чем-то means to encounter, to face, or to run into something.

Yes, it could be omitted.

Russian often leaves out subject pronouns when the meaning is clear from the verb form and context.

So these are both possible:

• Если ты когда-либо сталкивалась с такой задержкой...
• Если когда-либо сталкивалась с такой задержкой...

Including ты makes the address more explicit and personal. Omitting it can sound slightly more natural in some contexts, but both are grammatical.

Because скажи is the imperative of сказать, which is perfective and usually means:

• say
• tell
• give one complete response

That fits this sentence, because the speaker wants one answer: tell me what usually helps.

Говори is from говорить, which is imperfective and often means:

• speak
• keep talking
• go on, say it

So скажи is the natural choice here.

Yes. Скажи is singular informal, used with ты.

If you want the polite or plural form, use:

• скажите

Then the whole sentence would normally change too:

• Если вы когда-либо сталкивались с такой задержкой, скажите, что обычно помогает.

Here it means what.

So the phrase means:

• tell me what usually helps

A useful clue is that помогает needs a subject, and что fills that role:

• what usually helps?

If что meant that, the structure would be different.

Because обычно помогает means usually helps in a general sense.

The speaker is asking for a general pattern or remedy, not about one specific past event.

So:

• что обычно помогает = what usually helps
• что помогло = what helped once
• что обычно помогало = what used to help / what would usually help in past situations

The present tense is the most natural choice for a general statement.

It can be added, but it does not have to be.

Russian often omits мне when tell me is already obvious.

So both are fine:

• скажи, что обычно помогает
• скажи мне, что обычно помогает

Adding мне makes it a little more explicit.

Yes, Russian word order is flexible, but the original version sounds natural and neutral.

The sentence keeps things in a clear order:

• condition first
• then the request
• with когда-либо placed close to the verb it modifies

You may see other orders, but they often sound more marked or emphasize something different. For a learner, the original word order is a good model to follow.