Translation:Learning and practicing a language require patience.
Learning requires patience. Practicing a language requires patience. Learning and practicing a language require patience. "Requires" would be correct for a singular subject, but "require" is the correct conjugation for a plural subject.
Gerunds as subjects are a little bit special, and very often the singular verb agreement is used, especially when the activities are simultaneous or about the same thing (in this sentence, a language). Consider: 'Drinking and driving is very dangerous.'
I agree. It depends whether it is including or not. Learning AND practising as one thing, or two. To sum up, they should accept both, singular and plural.