numbers => [zero, uno, due, tre, quattro, cinque, sei, sette, otto, nove,
        dieci, undici, dodici, tredici, quattordici, quindici, sedici,
        diciassette, diciotto, diciannove,
        20 => venti, 30 => trenta, 40 => quaranta, 50 => cinquanta,
        60 => sessanta, 70 => settanta, 80 => ottanta, 90 => novanta,
        100 => cento
    ]
rules => [
        21,28,31,38,41,48,51,58,61,68,71,78,81,88,91,98 => {ten-1}{digit},
        22-99 => {ten}{digit},
        200,300,400,500,600,700,800,900 => {digit}cento
    ]
exponents => [
    singular => [mille, milione, miliardo, bilione],
    plural   => [mila, milione, miliardo, bilione], // TBD
],
separator => ''
replace => [unomille => mille]