All staff working for a body promoting the Welsh language are being offered the chance to leave their jobs under a voluntary exit scheme.
The changes in the office of the Welsh Language Commissioner, which employs around 45 people, are part of a restructuring.
Concerns have been raised that the commissioner intends to concentrate on regulation rather than promotion.
Pressure group Dyfodol i'r Iaith has called for a period of stability.
The post of Welsh language commissioner was established in April 2012 by legislation which obliges public bodies and some private companies, such as utilities firms, to provide services in Welsh.
Some of its duties were transferred from the now defunct Welsh Language Board.
"At that time the structure was inherited from an agreement between the Welsh Language Board and Welsh government officers," said a spokesperson for the commissioner, Meri Huws.
"As the organisation is developing and as new statutory powers come into force, the commissioner is undertaking a review of the original structure in order to create a structure which is better suited to the Welsh Language Commissioner's functions under the Welsh Language (Wales) Measure 2011."
Pressure group Dyfodol i'r Iaith (Future of the language) is concerned there has been uncertainty over who is responsible for promoting the use of Welsh.
"It is evident that it's a period of uncertainty for staff and also for standards. It has been an uncertain year," said chair Heini Gruffudd.
"We are looking forward to seeing stability and for some action. There has been uncertainty from the start who is meant to do what [in relation to regulation and promotion of the language].
"I think we're still in some sort of vacuum since the Welsh Language Board was dissolved."