I haven't finished reading the thread but my jaw is on the ground.
There are a few posters who get it, EileenGC and others, but my god, what are the rest of you on about?
I have been in the OP's position many times. (I couldn't take the train home from uni {in Wales, back to Wales} without going through Shrewsbury. Many of us who live in Aberystwyth, Pwllheli, wherever, will have had the experience of meeting a friend or neighbour on the platform at Wolverhampton or Shrewsbury or Euston and stting with them (and speaking whatever our common language may be together) all the way home.
I know all the people who think the OP is unreasonable aren't going to come back and read the thread, but this is for the lurkers.
Why do you think you should be able to understand whatever anybody else is saying??
When you are on holiday in Spain (or wherever) do you speak the local language with your family and friends? No, you speak English, your mother tongue.
If you were on the eurostar to Paris with your husband, would you speak French? or even Breton? Normand? Basque? or would you speak your mother tongue, English?
Turning back to your friend (or child/mother/husband) who speaks the same mother toungue as you do should not be a problem, and I am ABSOLUTELY AMAZED THAT ON A SITE I VISIT ALMOST EVERY DAY TO CONVERSE WITH OTHER PEOPLE IN ONE OF MY OTHER LANGUAGES (ie English), THAT OTHERS COULD EVEN BEGIN TO THINK THIS IS UNREASONABLE.
Please, think about this. The women whose words you are reading every day. Many, many, many of them are communicating with you in a language (English) which is not their first language!! I know that there are many Welsh women on here. There will also be many women who grew up speaking Gaelic in Scotland and Ireland, as well as all the speakers of Polish, Urdu, Punjabi, French or any other language.
When you come across us speaking Welsh Puujabi Urdu Arabic Hungarian Polish on a train we are not excluding you - we are simply speaking our mother tongue to our daugter/son/mother/friend...