When expressing a positive opinion about something, there are many phrases that can be used instead of "speaking in favor." One could say that they are "in support of," "advocating for," or "championing" a particular idea or cause. Another option would be to say that they are "proponents of" or "enthusiastic about" the subject. Additionally, one could use terms like "in agreement with," "endorsing," or "backing" to convey a positive stance. Ultimately, there are many ways to communicate a supportive opinion, and the choice of wording may depend on the context, audience, and tone of the conversation or presentation.