ERROR: 1-gram discount out of range for adjusted count 2

[Sundy1219]

Hi,I have a Chinese text,which have 6300440 lines,about 315MB it likes this:

I use the command lmplz -o 5 --prune 1 2 2 3 4 lm.arpa

The error ocurrs:

What is wrong with it ? How to resolve it ? Thanks @kpu

[kpu]

Does adding --discount_fallback fix it?

[Ltorrado]

it did for me, thank you.