There are a variety of synonyms available for the term "Old Welsh." Some of the most commonly used alternatives include "Ancient Welsh," "Early Welsh," or "Classical Welsh." These terms refer to the form of the Welsh language that was spoken between the fifth and twelfth centuries and is considered the precursor to the modern Welsh language. Other synonyms for "Old Welsh" include "Archaic Welsh," "Early Medieval Welsh," and "Proto-Welsh." Despite the variations in terminology, all of these terms refer to the same historical phase of the Welsh language and are used interchangeably by scholars, linguists, and historians who study the Welsh language and culture.