2012-08-08: This is now implemented in the radial branch. http://jsfiddle.net/highcharts/Phb2W/

2012-08-07: We propose to move these definitions out to the language object, as an array called lang.numericSymbols:

lang: {
numericSymbols: [‘k’, ‘M’, ‘G’, ‘T’, ‘P’, ‘E’]
}

Each item in the array is a multiple of 1000 of the previous. This also allows for other symbols, for example the implementer can define a symbol of ‘,000’ instead of ‘k’, or speak out the number as ’ thousands’ or ’ millions’. A value of null will skip the symbol altogether and use the full number formatting.