First, I use this for less than :
1=mi/un, 2=bi/duo, 3=tri/tre, 4=quadri/quattor, 5=quin(ti), 6=sex(ti), 7=septi/septen, 8=octi/octa, 9=noni/novem, 10=deci, 20=vigin(ti), 30=trigin(ti), 40=quadragin(ti), 50=quinquagin(ti), 60=sexagin(ti), 70=septuagin(ti), 80=octagin(ti), 90=nonagin(ti), 100=cen(ti), 200=duocen(ti), 300=trecen(ti), 400=quadracen(ti), 500=quincen(ti), 600=sexcen(ti), 700=septencen(ti), 800=octacen(ti), 900=novemcen(ti),
- If x<10, use left one's place words.
- (ti) is used when it comes before -illion.
- If 10<=x<100, right one's place word and ten's place word.
- If 100<=x<1000, use words in the order of 100,1,10.
And here's some definitions:
- tigh words are what is above, a number less than 1000.
- yoe words are anything but tigh ones, which is used in further extension.
- stop form is a form of word which illion comes right after it.
- tigh form is a form of word which a tigh word comes right after it.
- yoe form is a form of word which a yoe word comes right after it.
- phrase is words made from three digits and yoe words.
We can say that "mi," "bi," "tri" are stop forms and "un," "duo," "tre" are tigh forms.
Next, numbers up to comes.
(tigh and yoe form) 10^3=kilo, 10^6=mega, 10^9=giga, 10^12=tera, 10^15=peta, 10^18=exa, 10^21=zetta, 10^24=yota, 10^27=nea
For stop forms, erase the last vowel.
The number order is left-to-right( inverted in ten's and one's).
=novemcentinovemnonaginnea novemcentinovemnonaginyota novemcentinovemnonaginzetta novemcentinovemnonaginexa novemcentinovemnonaginpeta novemcentinovemnonagintera novemcentinovemnonagingiga novemcentinovemnonaginmega novemcentinovemnonaginkilo novemcentinovemnonagintillion
(I used space for easy to read, but the space shouldn't be.)