Problem vs. problems

[Kirara]

Test No. incompl/inter-7 "A Holiday Report", question 2

The problems I have ......... the language are to do with spelling.

(a) on
(b) to
(c) with

Test No. incompl/inter-7 "A Holiday Report", answer 2

The problems I have with the language are to do with spelling.

Correct answer: (c) with
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Hello teachers,

I understand that the answer for this question is 'with,' but I have another question regarding the sentence.

Why does the subject in the sentence have to be plural? 'To do with spelling' is shown as just one problem there, so in this case can we say this as follows?
'The problem I have with the language is to do with spelling.'

Could you please explain why the plural form is used in the sentence for me?

Many thanks for your help in advance.

[Alan]

An interesting question. Both singular and plural can be used here but I have chosen the plural really to show that spelling can present a whole range of problems and it isn't exclusively spelling because the phrase is to do with/concerning.
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English as a Second Language
You can read my ESL story Present Simple

[CraNeO]

I don't understand why can't say 'have problem on the language'?
Thx!

[Alan]

Using on doesn't work here because it is too precise. You need with because this means connected with/associated with and is used here to give the general idea rather than the specific.
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English as a Foreign Language
You can read my EFL story Progressive Forms