I'm staying with my in-laws in another country for a fortnight. They don't speak English so I have learnt their language and can speak it reasonably well. At home in the UK DH and I speak to each other in English all the time. Today my MIL has told DH that she wants me to speak only their language while I am staying at their house as she thinks it is rude that she can't understand everything we say - when all having a meal together or sitting together I generally speak their language, but if sitting separately with DH or just asking something quick like where we've put something etc I will usually speak in English. I'm also speaking more English in their house since having DCs as DS1 age 2 insists that I speak to him in English.
I think her request has been triggered because yesterday DH asked her if she minded if we went out for half an hour for a drink at a nearby bar and if she could call us straight away to come back if DS2 (3 months old and exclusively BF) woke up, she told him she would just pick him up until we came back and was upset that she didn't think that we could let her settle the baby (doesn't seem to bother her that she can't feed him which is the only reason he wakes at the moment!). DH decided he couldn't trust her to call us if needed and decided against going out and didn't tell me until today - but I think she must have thought we were discussing it in English last night.
As she hasn't asked me directly I've decided that I'm going to carry on as normal speaking their language or English when it feels appropriate as it is a lot of effort for me to speak their language all the time just so that they can always know what we are talking about! I extended an olive branch today by asking her to bath DS2 to show I trust her to look after him. Does this seem reasonable or AIBU and would others respect MIL and speak only their language?