When it comes to describing the way someone is speaking, "in soft tones" is a common phrase. However, there are several synonyms that can be used to convey a similar meaning. For example, "in hushed tones" suggests that the speaker is trying to keep their voice low, perhaps to avoid being overheard. "In gentle tones" implies a soothing or comforting quality to the voice, while "in mellow tones" suggests a softness or warmth. "In dulcet tones" is a more poetic phrase, often used in literature, and has a similar meaning to "in soft tones." Ultimately, the choice of synonym will depend on the context and the specific nuance or implication being conveyed.