After the initial letter S

for the second letter: 

use number: 

a

2

ch

3

e

4

hi

5

mop

6

t

78

u

9

After the initial letter Qu

for the second letter: 

use number: 

a

3

e

4

i

5

o

6

r

7

y

9

After other initial consonants

for the second letter: 

use number: 

a

2

e

4

i

5

0

6

r

7

u

8

y

9

After initial vowels

for the second letter: 

use number: 

b

2

d

3

lm

4

n

5

p

6

r

7

st

8

uy

9