Gall y system gynllunio helpu i greu’r amodau cymdeithasol ac economaidd sy’n rhoi cyfle i bobl siarad Cymraeg, er enghraifft drwy gefnogi datblygiad economaidd a darparu tai fforddiadwy yn y cymunedau lle nodir gan yr awdurdodau cynllunio lleol bod y Gymraeg yn ystyriaeth o bwys. Er bod TAN 20 yn rhoi canllawiau penodol ar gynllunio a'r Gymraeg, ni ddylai gael ei ddarllen ar wahân i ddogfennau polisi perthnasol eraill.  Mae Polisi Cynllunio Cymru, TAN 2: Tai Fforddiadwy a TAN 6: Cymunedau Gwledig Cynaliadwy, oll yn cynnwys darpariaethau perthnasol i’r her o gynnal cymunedau Cymraeg eu hiaith
The Planning system can help create the social and economic conditions which give people the opportunity to speak Welsh, for example by supporting economic development and providing affordable housing in those communities where the Welsh language has been identified by local planning authorities as a significant issue. Although TAN 20 provides specific guidance on planning and the Welsh language it should not be read in isolation from the other relevant policy documents. These include Planning Policy Wales and our advice notes on Affordable Housing (TAN 2) and Planning for Sustainable Rural Communities (TAN 6), which contain provisions relevant to the challenge of sustaining Welsh speaking communities.