I know about "step up to the plate" - but I'd question whether it has ever come into general use East of the Atlantic.

McGrath, as I gave the original example, from Australia, I'm wondering whether we're East of the Atlantic. And your comment about origins of the game "went straight through to the keeper", another expression in common use here.

the use of sounds like "Hmmm;"
Four decades ago I was one of the six Melb. Uni Mountaineering Club climbers to complete the full Arthurs Ranges traverse in SW Tasmania; from recollection we were the fourth group to do so in a time when there were no maps. It took us three weeks and, about half way through, we experimented with using "Hmmm" as our only verbal communication for the next day's effort.

Making meals, striking and making camp, reaching navigational decisions, admiring the view, cursing the weather, taking scroggin stops, "Hmmm" managed it all; a most versatile vocalisation.

On the matter of vocabulary sizes, I forget the exact source but, when I was teaching first-year biologists, it was understood that a university matriculant with no formal biology education would have a useable vocabulary of about 10,000 words. By the end of their first year, successful biology students would have doubled their vocabulary. As Peace has observed, many would be "recognition or recall vocabulary"; even so, the technical "jargon" becomes part of their working vocabulary while they practise in the field.

Cheers, Rowan