IPA

• Linguists and speech-language pathologists use the International Phonemic Alphabet (IPA) to record transcripts of speech. Some of its characters look very similar to that of English, but there are more characters in the IPA than in English because it is intended to transcribe sounds in multiple languages from around the world.
  
  

Phonetics

• Phonetics is the description and classification of sounds. Most people have heard of consonants and vowels. The main difference between them is that vowels are produced without any constriction within the vocal tract, and consonants are produced with some sort of constriction. Consonants are classified by where the constriction occurs. For example, sounds like m, n, and ng are classified as nasals, because that is their point of articulation.
  
  

Phonology

• Phonology incorporates many of the same terms and concepts as phonetics, but it looks at them in a more holistic light, as they function in the broader language. In other words, phonetics describes individual sounds, phonology describes the language. An application of this would be if you had a child from an English-speaking area that used clicking sounds to communicate, the child would have a disordered phonology because this sound is not found in her native tongue. If the child was from an area where this was part of her language, this would not be a disordered pattern, it would be part of her normal phonological development. Phonetics gives the tools to describe the sound the child is making, and phonology gives the broader picture of whether it is normal or not.
  
  

Transcription

• A speech-language pathologist uses transcription to diagnose and treat speech and language problems, and a speech transcript also allows linguists to compare language patterns. Transcription used to be done entirely by hand, and sometimes still is, but the IPA has created fonts for professionals to use in word-processing programs. Transcription and analysis of languages help scholars understand migration patterns by noting where languages branch off from one another, or new features are adopted, which can suggest new settlers or other social changes.