At EGLL I found that a number of pilots would call up on the new frequency to state 'monitoring', which is not the intention at all. I, and a significant number of others, used the non-standard word 'Listen' e.g. 'Listen 118.5 Good-Day' which had a significantly better success rate than 'monitor'. 'Listen' was much better understood by less than Level 6 English speakers although sometimes some Brits would interrupt by piping-up 'Hello, X listening 118.5'. A certain infamous outspoken ATCO (and I occasionally...) would be moved to reply 'no you're not you're transmitting, I-will-call-YOU'. I believe that the intention of the word 'monitor' has changed over the years. I believe its intention was to listen to a broadcast rather than change freq and wait to be called but 'Wait to be called on 118.5' is not compatible with 'one word-one meaning'.