Hyvaa Pyvaa! (Good morning in Finnish if I´m not mistaken)
A phoneme is a unit of sound that distinguishes one word from another in a particular language. Hence the example of <em>Kate </em>and <em>Kade </em>in Finnish shows us that these are separate words (i.e. with different meaning) because they are distinguished by their respective phonemes, <em>t </em> and <em>d.</em>