There is a phenomenon called epenthesis where a sound, usually vocalic, is inserted between other sounds, usually consonantal, to help out in pronunciation (or phonotactics). You hear it in some pronunciations of realty (reeluhtee) and nuclear (nookooler).

The reason English has so many silent letters is because our orthography (spelling system) went out of whack with how words were being pronounced about 600 years ago but we never released new versions.

Ceci n'est pas un seing.