Rule of thumb is that thematic は rarely appears in subordinate clauses (and then only in certain types, not in a こと clause), however, there is no such restriction for contrastive は.
According to the DOJG, the topical は is not usually used in subordinate clauses. That said, you’re still allowed to use multiple はs in a sentence. Normally, the first marks the topic while subsequent はs tend to be increasingly contrasting.
In your case, if you’re trying to mark 貴方は言っていること as the topic, you should use が for the first はbecause that clause is subordinate. However, what you have written still works, albeit differently from what you may have intended. あなた is the topic, and 言っていること is understood to contrast with something else mentioned previously.
3 comments
It depends on what nuance you want to portray
Rule of thumb is that thematic は rarely appears in subordinate clauses (and then only in certain types, not in a こと clause), however, there is no such restriction for contrastive は.
According to the DOJG, the topical は is not usually used in subordinate clauses. That said, you’re still allowed to use multiple はs in a sentence. Normally, the first marks the topic while subsequent はs tend to be increasingly contrasting.
In your case, if you’re trying to mark 貴方は言っていること as the topic, you should use が for the first はbecause that clause is subordinate. However, what you have written still works, albeit differently from what you may have intended. あなた is the topic, and 言っていること is understood to contrast with something else mentioned previously.