Tone and teaching

I was talking to a colleague about tone and intonation. I gave an example about how we use a stronger downward pattern to sound strong or rto eprimand and a light, sing-song cadence when don't want to offend someone or show a lower status. We use high lifts to encourage people. However, I never thought about if we use too many high pitches while teaching, it can sound too cheerful, like fake praise, and lower our status as teachers. It's especially tricky when teaching college level because they want to be treated like adults or near-equals. However, they need guidance and sometimes have bad behavior and deserve to be reprimanded. The wrong tone makes them feel discouraged or that someone is talking "down" to them. I think this must be very difficult for non-native speakers, no matter how fluent they are in English. Even within English dialects, intonation causes terrible misunderstand. I've read that Indians in England can sound rude when they intend to show respect due to cultural differences in how intonation is used.