I'll put something up from the book I'm reading, Teach Yourself Books C. J. Dunn and S. Yanada Japanese (first printed 1958, impression 1973):
In lesson 7 (p. 29)
"A standardized adjectival clause is used as one of the ways of expressing the idea of "being able". Thus yomu koto ga dekimasu is equivalent to "I can read"; in other words, to add the idea of "being able" to any verb, put the plain form of the verb before the expression kota ga dekimasu. Thus, to give another example, Eigo o hanasu koto ga dekimasu can be translated as "Can you speak English?" The expression koto ga dekimasu is best thought of as idiomatic; koto is "an abstract thing" and dekimasu, or dekiru, to use the dictionary form, as we shall henceforth when referring to a verb, is a word of wide meaning, including such as "is made", "is produced", "is possible"; you may thus think of yomu koto ga dekimasu as "a reading thing is possible" or "reading is possible", but it is probably better not to analyse the meanings of the expressions such as this. However, the construction composed of a verb followed by koto is a useful one, for it can be used to translate English verbal noun ending in "-ing". Thus yomu koto is "reading", oyogu koto, "swimming", hanasu koto, "speaking", e.g., Nihongo o hanasu koto wa muzukashii desu. Speaking Japanese is difficult. Or It is difficult to speak Japanese."
I am here to further my understanding of this noun.
(Glossary: koto n. (abstract) thing, fact)
I recommend looking up the definition for idiomatic. This is probably why it is hard to translate because there is not a literal meaning that is necessarily obvious. This book gave me some useful examples, but even so I need more examples before I can truly understand koto.