in English is:

efficiency

Mutations

Soft:(no mutation)
Nasal:(no mutation)
Aspirate:(no mutation)

Use

yr effeithlonrwydd hwn
fy effeithlonrwydd i
dy effeithlonrwydd di
ei effeithlonrwydd ef/o
ei heffeithlonrwydd hi
ein heffeithlonrwydd ni
eich effeithlonrwydd chi
eu heffeithlonrwydd nhw/hwy
Phrases (1)
arbedion effeithlonrwydd
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