Only about 2260 of the approximately 6800 known languages and dialects on planet Earth have writing systems. Those that have had them for some time have felt the influence of the writing system on pronunciation.
Generally, a writing system is supposed to capture the sounds of the language it represents (Chinese being the notable exception). However, sometimes the influence moves in the opposite direction. The pronunciation of the T in the word often is a prime current example.
T doesn’t like to stand between F and a vowel—soften is another case in point. So the T should not be pronounced. However, seeing it there as we read makes it difficult to ignore, so some people pronounce it.
The same thing happened to gerrymander. Gerry today is used most often as a nickname for Gerald or Geraldine where the G is soft. Since it looks like it should be soft, it has become soft, even though the OED still offers the hard version as the basic one.