1 low pitch

2 quiet (voice)

3 subdued

4 low-key

5 low-profile

1 to coordinate

2 to harmonize

3 to fit together

4 to match (colors etc)

5 harmonious

6 concerted

1 to emphasize (a statement)

2 to stress

1 sentiment

2 tone and mood

3 taste

1 air conditioning

2 air conditioner (including units that have a heating mode)

3 classifier: 台 tái

1 to sing the high part

2 to speak fine sounding but empty words (idiom)

1 monotonous

2 dull

3 tedious (idiom)

1 to speak with a foreign accent or using words from a foreign language (usually derogatory) (idiom)

1 the hardships of beginning an undertaking (idiom)

1 to play the same old tune (idiom); unoriginal