Every language has an inventory of phonemes (individual meaningful sound units). Different languages have different inventories. Many languages have phonemes in common, while some have phonemes that are more unique. The International Phonetic Alphabet (IPA) was invented during the late nineteenth century by the International Phonetic Association, an orthographic system capable of symbolically representing all of the phonemes produced in human oral communication, regardless of the language in which they appear. The alphabet has undergone many revisions since its first iteration. The following graphic illustrates some of the places in the oral cavity where known phonemes are produced and the IPA symbols representing them.