One of the most difficult elements of learning English is its complex spelling structure. The relation between sounds and the way they are written is often inconsistent and may be pretty complicated. For example, the vowel schwa /ə/ may be spelled in as many as 43 different ways! The spelling of many English sounds may be quite treacherous – an identical combination of letters may be realized as completely different sounds. For example, the spelling of <read> may mean a verb in the Present Tense or an Infinitive pronounced as /rid/, but it may also mean a verb in the Past Tense pronounced as /red/, while the spelling of <ch> may be realized as /ʧ/ (e.g. chair), or /ʃ/ (e.g. champagne), or /k/ (e.g. technology). For that reason, all graphemes (i.e. the letters that represent the actual sound) in the program have been highlighted. This allows the user to learn the relations between the sounds and the ways they are spelled. This is a toggle (on/off) function in the menu “Options”, so the highlighting is optional.