From Apertium

IRSTLM is a free and open source exact statistical language model using memory-mapping. The language models are compatible with those created with the closed-source SRILM Tooolkit.

See the homepage at http://hlt.fbk.eu/en/irstlm

[edit] See also

• Moses (has IRSTLM installation instructions)
• Using GIZA++
• RandLM - a randomised LM, based on Bloom Filters