For some writers, their main spelling problem is similar-sounding words, for example, principle and principal or affect and effect. These problems cannot be flagged by software spell-checking functions. Here is a list of these commonly confused homophones (different spelling; same or very similar pronunciation), with examples of their correct use. All definitions in this section are from the Merriam Webster dictionary via the Merriam Webster Dictionary mobile application.
McMurray, David and Reardon, Tiffani, "32. Common Spelling Problems" (2016). Sexy Technical Communications. 32.