Learn Hardcore Chinese: Tā jiā de jīngjì bú tài hǎo, xuéfèi duì tāmen láishuō shì yì gè dà wèntí. - His family’s finances aren’t very good; tuition is a big problem for them.

他家 = “his family / his household” (or “his home” depending on context)
的 marks possession or attribution.
经济 literally means “economy”, but in this phrase it means “financial situation / finances”.

So 他家的经济 is structured as:
[他家] 的 [经济] → “the financial situation of his family”.

Why is there no 的 between 他 and 家? Could I say 他的家 instead of 他家?

Both 他家 and 他的家 are possible, but they feel slightly different:

他家 (no 的) is very common and natural in speech.
- Used with close relationships or “inherent” relations: 他家, 我妈, 他们学校, etc.
- Feels neutral, everyday, and a bit more concise.
他的家 (with 的) is also correct, but:
- Sounds a bit more formal or emphatic.
- Can emphasize “his (and not someone else’s) home”.

In this sentence, 他家的经济 is the most natural and idiomatic way to say “his family’s finances”.

Does 经济 here mean “the economy” (like a country’s economy), or something else?

经济 can mean both:

Macro sense: a country’s economy
- 中国的经济发展得很快。
  “China’s economy is developing very fast.”
Personal sense: someone’s financial situation / finances
- 他家的经济不太好。
  “His family’s finances are not very good.”

In this sentence it is clearly the personal / household sense: “his family’s financial situation”.

What exactly does 不太好 mean? Is 太 here “too” (as in “too good/bad”) or “very”?

In 不太好, 太 does not mean “too (excessively)”. It acts more like “very”:

太好 (by itself) normally means “too good / extremely good”.
But 不太 + adjective is a fixed pattern meaning “not very …”.

So:

不太好 ≈ “not very good / not so good” (a mild negative).
不好 ≈ “not good” (more direct).
很不好 ≈ “very bad” (stronger negative).

Here, 不太好 softens the tone: his family’s finances are not very good, but it doesn’t sound as harsh as “terrible” or “really bad”.

Why is 不 pronounced bú in 不太好 instead of bù?

This is a case of tone sandhi (tone change):

不 is normally 4th tone: bù.
When 不 is followed by another 4th tone, it changes to 2nd tone: bú.

In the sentence:

不太好 → the next syllable 太 is 4th tone (tài), so 不 becomes bú → bú tài hǎo.

Other common examples:

不对 → bú duì
不是 → bú shì
不要 → bú yào

When 不 is followed by a 1st, 2nd, or 3rd tone, it usually stays bù (4th tone), e.g. 不忙 (bù máng).

Is there also tone sandhi on 一 in 一个大问题?

Yes.

一 (yī) also changes tone depending on what follows:

Before a 4th tone, 一 becomes 2nd tone: yí.
Before a 1st, 2nd, or 3rd tone, it usually becomes 4th tone: yì.

In 一个大问题:

个 is 4th tone (gè), so 一 changes to yí.
Pronunciation: yí gè dà wèntí.

Spoken naturally, you’ll typically hear yí gè, not yī gè.

What does the pattern 对……来说 mean in 学费对他们来说是一个大问题?

对……来说 is a set phrase meaning roughly “for … / as far as … is concerned / from the perspective of …”.

Structure:

对 + someone + 来说, + sentence
- 对他来说，这份工作很好。
  “For him, this job is very good.”
- 对我来说，中文不太难。
  “For me, Chinese is not very hard.”

In your sentence:

对他们来说 = “for them / as far as they are concerned”.
学费对他们来说是一个大问题 ≈ “Tuition, for them, is a big problem.”

“来说” literally means “to speak” (“speaking in terms of …”), but here it’s a fixed grammatical chunk.

Can 对他们来说 be moved to the beginning of the sentence? Is 对他们来说，学费是一个大问题 also correct?

Yes, both word orders are correct:

学费对他们来说是一个大问题。
对他们来说，学费是一个大问题。

They mean the same thing. The difference is just emphasis/focus:

Version 1 starts with 学费 (tuition) → slightly more focus on “tuition”.
Version 2 starts with 对他们来说 → slightly more focus on “for them / from their standpoint”.

Both are very natural.

Why is it 他们 (“they”) in 对他们来说 and not 他 (“he”)?

Here, 他们 refers to his family as a group, not just to him alone.

The first part:

他家的经济 = his family’s finances.

Then:

对他们来说 = “for them” → referring to all the members of that family.

It would be odd (and less logical) to say “tuition is a big problem for him” when you’ve just described the finances of the whole family. So the plural 他们 matches that idea of the family as multiple people affected by the tuition.

Why do we need 是 in 学费对他们来说是一个大问题? Could we leave it out?

Here 是 links the subject to a noun phrase predicate:

学费 (tuition) = subject.
一个大问题 (a big problem) = noun phrase predicate.

In Chinese:

When the predicate is a noun, you typically use 是:
- 他是老师。 – “He is a teacher.”
- 这件事是一个大问题。 – “This matter is a big problem.”

If the predicate is an adjective, you do not usually use 是:

学费很贵。 (not 学费是很贵 in neutral statement)
他很好。

So:

学费对他们来说是一个大问题。 ✅ natural.
学费对他们来说一个大问题。 ❌ sounds incomplete in standard Mandarin.

You generally should keep 是 here.

Why do we need the measure word 个 in 一个大问题? Could I just say 一大问题?

Chinese almost always needs a measure word (classifier) between a number and a countable noun.

一 + 个 + 问题 → “one problem”
So 一个大问题 = “a big problem”.

个 is the default, very common classifier, and 问题 can take 个:

一个问题 / 两个问题
这个问题 / 那个问题

一大问题 exists, but:

It’s more literary or used in certain set expressions.
In everyday speech, 一个大问题 or 是个大问题 is much more natural.

So in this sentence, (是)一个大问题 is the normal form.

Could we say 学费对他们来说是个大问题 instead of 是一个大问题? Is there any difference?

Yes, 是个大问题 is very natural and actually more common in speech than 是一个大问题.

Nuance:

是个大问题: feels a bit more colloquial and smooth.
是一个大问题: a little more explicit; can slightly emphasize “one big problem” (as one among several), but often the difference is minimal.

Both are grammatically correct. In everyday conversation, many native speakers would say:

学费对他们来说是个大问题。

Can we drop 来说 and just say 学费对他们是一个大问题?

You can say 学费对他们是一个大问题, and it is understandable and not wrong, but:

对他们来说 strongly signals “from their point of view / for them” (viewpoint).
对他们 alone can feel a bit more like “with respect to them / as it affects them”, and is more often used in patterns like:
- 对他们有影响 – “have an impact on them”
- 对他们不公平 – “be unfair to them”

In the specific expression “X 对 someone 来说，是一个大问题”, the 来说 is very common and idiomatic.
So:

学费对他们来说是一个大问题。 ✅ most natural for “For them, tuition is a big problem.”
学费对他们是一个大问题。 ✅ grammatically OK, but slightly less “standard-sounding” for the “from their perspective” meaning.

Why is there a comma ， in the middle of the sentence in Chinese, where English would probably use a period or “and”?

Chinese punctuation is a bit more flexible:

The comma ， often separates two closely related clauses in a single sentence.
Your sentence has two parts:
1. 他家的经济不太好 – His family’s finances aren’t very good,
2. 学费对他们来说是一个大问题 – (so) tuition is a big problem for them.

In English you might write:

“His family’s financial situation isn’t very good, so tuition is a big problem for them.”
or
Two separate sentences with a period.

In Chinese, it’s very natural to link them with just a comma without an explicit “so” (所以). The logical connection (“therefore”) is understood from context.