When "oe" occurs in French without the ligature, it is pronounced , just like words spelt with "oi". The most common words of this type are ' ("stove", "frying pan") and ' ("soft"). Note that "poêle" is itself an etymological spelling, with the "ê" reflecting its derivation from Latin '. If the "oe" is not to be pronounced thus, then a diaeresis, acute or grave accent needs to be added in order to indicate that the vowels should be pronounced separately. For example, ', ', '. The exception to this rule is when a morpheme ending in "o" is joined to one beginning in "e", as in ', or with the prefix "co-", which is always pronounced in hiatus with the following vowel, as in ' ("ratio", "coefficient").