Phonetics is the study of speech sounds, focusing on how they're produced, transmitted, and perceived. It examines the physical aspects of speech, from the vocal tract to sound waves, and provides a systematic way to describe and classify sounds across languages. Speech sounds are the building blocks of spoken language. Phonemes are the smallest units that distinguish words, while allophones are variations of phonemes. Consonants involve constriction in the vocal tract, while vowels are produced without significant constriction. The International Phonetic Alphabet (IPA) standardizes the representation of these sounds.