nl_tokens: Some keys contain a disambiguation mark : Eko~ca vs Eko~gr If so we save these in an ambiguous object for later use
pl_tokens: function checkAmbiguous ( k ) { let i = k . indexOf ( '~' ) ; if ( i !== - 1 ) { let stem = k . substring ( 0 , i ) ; ambiguous [ stem ] = true ; return true ; } return <mask> ; }