I like your list of stock phrases. I've had solo days in the office where I could manage with just two ("thankyou" to the bus driver and "skim flat white please" at the coffee shop), but don't think I could handle actual interaction with people on so few.

With regard to physics insertions, you can explain quite a lot with a limited vocabulary: c.f. Up Goer Five http://xkcd.com/1133/...