Voiced Alveolar Fricative - Voiced Apico-alveolar Fricative

The voiced apico-alveolar fricative, is a fricative which is articulated with the tip of the tongue (apex) against the alveolar ridge. It is the sibilant found in dialects of central and northern Portuguese, several dialects of European Spanish, Antioqueño Spanish, Catalan, Gascon, Languedocien Occitan, and Modern Greek. Often to speakers of languages or dialects which do not have an apico-alvolear fricative, they are said to have a "whistling" quality.