Interdental consonants are produced by placing the blade of the tongue against the upper incisors. This differs from a dental consonant in that the tip of the tongue is placed between the upper and lower front teeth, and therefore may articulate with both the upper and lower incisors, while a dental consonant is articulated with the tongue against the back of the front incisors.

Although this articulatory configuration is by no means exotic in the sense that it involves the tongue blade and the upper incisors, both frequently employed in the formation of other consonants, interdental realisations of consonants are rare cross-linguistically. Interdental realisations of otherwise dental consonants do appear to be more frequent as idiosyncrasies or due to coarticulatory effects of a neighbouring interdental sound. The most commonly occurring interdental consonants appear to be interdental non-sibilant fricatives. Interdental consonants do not appear to contrast with dental consonants.

Voiced and voiceless non-sibilant interdental fricatives appear as realisations of the initial sounds in American English in words like 'then' and 'thin'. In British English, these sounds are more likely to be dental.

An interdental /l/ occurs in some varieties of Italian, and may also occur in some varieties of English, though the distribution and usage of interdental /l/ in English are not clear.