1. (n.) A single unvaried tone or sound; a person who speaks in a single tone\.

2. (n.) The utterance of successive syllables, words, or sentences, on one unvaried key or line of pitch.

AF Indian file alliterating alliteration alliterative array articulation assonance assonant audio frequency banausic bank belabored blah buzz catena catenation chain chain reaction chaining chanting chime chiming cliche-ridden clockwork regularity concatenation connection consecution constancy continuum course cycle daily round descent dim dingdong dreary drone droning endless belt endless round even pace even tenor file filiation frequency fundamental fundamental tone gamut gradation harmonic harping hum humdrum intonation invariability jingle jingle-jangle jog-trot labored line lineage monologue monotonic monotonous monotonousness monotony near rhyme nexus orderliness overtone partial partial tone pedestrian pendulum periodicity pitch pitter-patter plenum poky powder train progression queue range rank recurrence regularity repeated sounds repetitiousness repetitiveness reticulation rhyme rhymed rhyming rotation round routine row run sameliness sameness scale sequence series single file singsong slant rhyme smoothness soniferous sonorous sounded sounding spectrum stale repetition stodgy string succession swath tedious tedium thread tier tonal tone toneless tonelessness train treadmill trot undeviation undifferentiation unnecessary repetition unvariation windrow