Fixed intonation refers to a consistent pitch or tone used while speaking. There are several synonyms for fixed intonation, including monotone, level, flat, unvarying, even, and uniform. Monotone refers to a constant, unchanging pitch; Level implies a steadiness of pitch without any fluctuations; Flat suggests a lack of inflection or variation in tone; Unvarying means the same pitch is maintained throughout; Even denotes a consistency of pitch without any abrupt changes; and Uniform implies a sameness or consistency in pitch. These synonyms all describe a speaking style where the pitch remains constant and may lack emotional or expressive variation.