Further golfing this C# code from Scramble words while preserving their outlines
As I am using linq in my program, I can change ToCharArray to ToArray to save 4 bytes.

I can also change the namespace around to be either System.Linq or System.Text.RegularExpressions to save a further 6 bytes by removing the using for it:

namespace System.Text.RegularExpressions


As @MartinEnder♦︎ points out in the comments I can save 10 bytes by re-ordering the groups in the regex and changing [A-Za-z] to \p{L}:

\p{L}(([gpqy])|(i|t)|(j)|([bdf-l])|([a-z]))*?[a-z]?\b