In S4, a distinction is made between consonants that are pronounced differently when they come before a vowel and when they come after one, in a syllable.

For instance, in the word “little”, the L-Sound occurs twice, but it is not said in the same way. The word is accordingly written lit‛l. The first L-Sound  is called a Clear-L, and the second a Dark-L. The Dark-L is often very difficult for a non-native speaker to pronounce, and the difference needs to be highlighted. Dark consonants are very common.

Examples:

even      iiv‛n
awful     oof‛l
rhythm   rið‛m

It could be argued that all the apostrophes, accordingly needed, make S4 text ugly and that if it is accepted as a rule that when a consonant ends a syllable it is automatically dark, then this does not need to be indicated. However, in multi-syllable words this might make it necessary to add mid dots to avoid ambiguity as to where the syllables divide. On this basis, if S4 were used for communication between native English speakers, the apostrophes could indeed be left out. However, S4 is primarily intended for non-native speakers and the difference in the pronunciation of light and dark sounds.