The proposals by Northern Ireland Secretary Julian Smith and Irish Tanaiste Simon Coveney on Thursday night include the appointment of an Irish language commissioner.
They also include a central translation hub to provide Irish language services in Government, as well as the repeal of an act dating from 1737 which bans the use of Irish in courts.
Similar measures, including a commissioner, will be put in place for Ulster-Scots.
Business at the Assembly may be conducted in both languages as well as English, with a simultaneous translation system as seen in the EU institutions.
An office of identity and cultural expression to promote respect for diversity, build social cohesion and reconciliation and support all aspects of cultural and linguistic heritage will be established.
In a statement, the Orange Order said the draft deal had been released with a "purposely narrow window for meaningful consideration".
"It is clearly far-reaching in its provision for the Irish language and its subsequent future role in the political and civic life of Northern Ireland," the statement reads.
"In contrast to the detailed list of measures to promote the Irish language, references to Ulster Scots/Ulster-British culture are ambiguous - lacking meaningful detail or delivery mechanisms.
"As British citizens living in the United Kingdom, we have a complex and multi-layered identity which in many areas is wider than simply 'Ulster Scots'.
"We remain unconvinced that the cultural traditions and identity of the Orange family will be meaningfully promoted or safeguarded by these proposals."