That is actually completely irrelevant to this conversation. The important part for Twitter's revenue, and the part they include in their financial statements, is about how many tweet reads are fake - that is what advertisers care about, since they don't pay per tweet, they pay per impression. That's what the 5% official estimate is about - how many Twitter readers are actually bots? This can't be estimated from tweet text regardless of how well you analyze it (especially since the overwhelming majority of tweeter users never send a single tweet).

Even if 100% of all tweets were generated by bots, as long as real people come to Twitter to read them and occasionally click on ads that Twitter shows them, Twitter's revenue is secured.