The answer is “communicating,” since we need a verb. While it is true that the gerund is technically a noun, it is also a non-finite verb form. If we try inserting a typical noun (instead of a gerund) into the sentence, it will sound wrong to anyone who is sufficiently familiar with English. Let’s look at another example.
Though she couldn't speak a word of Tibetan language, this did not really stop her from *baseball games with local people.
Though speak couldn't say a word of Tibetan language, this did not really stop her from playing baseball with local people successfully.
Btw, I changed “say” to “speak,” which works better in this context.