Any difference in meaning: "They differ in language" and "They differ in languages"

(I am not a native english speaker but a translator asking help for better translation)

I saw the expression, "All these differ from each other in language" and thought it is a typo of 'languages'. But having a typo in the first paragraph of a book is hard to swallow. Here is the actual sentence:

All these differ from each other in language, customs and laws

Just wondering if this "language" isn't a typo but is used to mean something different.

You can see the whole page including the above sentence here: https://buk.io/@10657/1/31665-31806?t=2CK

Solution 1:

I thought this sounded like Caesar. "Language" in the singular is fine: ie. they differ in the language spoken in each region. With "languages", you might get the sense that multiple languages were spoken in each region which Caesar was not suggesting. Moreover, Caesar himself uses the singular "lingua" in the original Latin; only "customs" and "laws" are in the plural in the original text.

Gallia est omnis divisa in partes tres, quarum unam incolunt Belgae, aliam Aquitani, tertiam qui ipsorum lingua Celtae, nostra Galli appellantur. Hi omnes lingua, institutis, legibus inter se differunt.

I've highlighted the three words in question.

It might be of interest to point out that in Caesar there is no "et"="and", or any of its various equivalents, connecting these three differences. So, in the original there is a sense that there are possibly other differences, but these are the only three Caesar chooses to highlight.