monotonous

Sounded or spoken in an unvarying tone.

Tediously repetitious or lacking in variety. synonym: boring.

Characterized by monotony; continued in the same tone without inflection or cadence; unvaried in tone.

Unvarying in any respect; tiresomely uniform.

Uttered in one unvarying tone; continued with dull uniformity; characterized by monotony; without change or variety; wearisome.