source: Evidence from countries around the world, over a number of decades, shows that there is a strong correlation between the viability and survival of a language and the existence of geographical areas where that language is considered to be the predominant language. 
target: Mae tystiolaeth o wledydd ar draws y byd, dros nifer o ddegawdau, yn dangos bod cyswllt cryf rhwng hyfywedd a goroesiad iaith a bodolaeth ardaloedd daearyddol lle ystyrir yr iaith honno fel y brif iaith. 