Words

Gus Polly

0zero10twelve20twentel
1one11twelve-one30thirtel
2two12twelve-two40fortel
3three13twelve-three50fiftel
4four14twelve-four60sixtel
5five15twelve-five70seventel
6six16twelve-six80eighttel
7seven 17twelve-seven90ninetel
8eight18twelve-eightT0tentel
9nine19twelve-nineE0eleventel
Tten1Ttwelve-ten 100one gross
Eeleven1Etwelve-eleven 200two gross
1 000one great2 000two great 10 000twelve great
100 000one gross great 1 000 000one second great1 000 000 000one third great
10^(3n) one (n)th great
Other than replacing the -ty (from ten) with the -tel (from twELve) suffix, this system uses the words that are already there. Also, when approaching large numbers, we no longer have to worry about what prefix goes before the -illion, we just need to know how many sets of three digits there are, and know that it's that many greats.

Ordinal forms

1first2second3third4fourth
5fifth6sixth7seventh8eighth
9ninthTtenthEeleventh10twelfth
10twelfth20twentelth30thirtelth40fortelth
50fiftelth60sixtelth70seventelth80eightelth
90ninetelthT0tentelthE0eleventelth100grossth

For convenience here, T stands for ten and E for eleven).