The word "vociferant" is spelled with the stress on the second syllable: /vəˈsɪfərənt/. To add the word "more" as a comparative, the spelling should be "more vociferant" with the stress remaining on the second syllable. The phonetic transcription for the word with the comparative would be /mɔːr vəˈsɪfərənt/. The word describes someone or something that is more vehement or forceful in their expression. So, if someone is being more vociferant, they are speaking with even greater energy and intensity than before.
The word vociferant is derived from the Latin word vociferari, which means to shout or to yell. The prefix more adds the sense of additional or increased.
Therefore, more vociferant basically means more vehemently shouting or more loudly proclaiming.