_t_, in a few words.

18. _When is D silent?_
Before _g_ in the same syllable.

19. _When is G silent?_
Before _m_ or _n_ in the same syllable.

20. _When is H silent?_
After _g_ or _r_ in the same syllable; and _h_ final after a
vowel is always silent; also, in a few words after _t_, and
initial in a few words.

21. _When is L silent?_
After _a_ when followed by _f_, _m_, _k_, or _v_, except in the
word valve; also, before _d_ in could, etc.

22. _When is M silent?_
Before _n_ in a few words.

23. _When is N silent?_
Final after _l_ or _m_.

24. _When is P silent?_
Initial before _n_, _s_, or _t_.

25. _When is S silent?_
In a few irregular words; as, _isle_, _puisne_, _viscount_,
_corps_, etc.