General synonyms:
* Out loud
* Orally
* Vocally
* Audibly
* Loudly (implies volume)
* Distinctly (implies clarity)
More specific synonyms:
* Articulately (implies clear and skillful speaking)
* Fluently (implies smooth and effortless speaking)
* Distinctly (implies clear and separate from other sounds)
* Plainly (implies simple and straightforward speaking)
* Solemnly (implies a serious tone)
* Cheerfully (implies a happy tone)
* Angrily (implies an angry tone)
Informal synonyms:
* Out in the open
* For all to hear
* In a clear voice
The best synonym to use will depend on the specific context of the sentence.