ALPHA, the first letter in the Greek Alphabet, may be pronounced as the "a" in "cat".
It is transliterated simply as "a".
ALPHA + IOTA is transliterated sometimes as AI, AE, or E.
The greek term AISTHESIS (sensation) is the root of the
English ESTHETICS, AESTHETICS, or ÆSTHETICS.

BETA may be pronounced as the english "B".

GAMMA may be pronounced as the english hard "g", as in "grab". GAMMA may appear in combination with other letters.
GAMMA combined with GAMMA is like N followed by G. For example, the greek word AGGELOS is transliterated as ANGELOS (angel).
GAMMA combined with KAPPA is like N (or ng) followed by K. For example,the greek word OGKOS (mass, tumour), is transliterated as ONCOS or ONKOS, as in the English "oncology" (study of cancer).

Delta may be pronounced as the English "D". Because of the shape of the upper case letter, "delta" has come to mean a triangular structure such as the Nile Delta or Mississippi Delta.

EPSILON may be pronounced as the short "e" sound, such as in "best" or "let".

ZETA may be pronounced as "Z" or as "DZ".

ETA is variously pronounced: some pronounce a long "e", as in "sleep", others use a long "a" as in "fate". Sometimes it is transliterated simply as "e", sometimes as "e" with some special marking, such as "é".

theta, iota, kappa, lambda, mu, nu, xi, omicron, pi

THETA may be treated as the "TH" in "theatre" or "theology" (both words of Greek Origin). It is better not to pronounce it with vocalization, as the "TH" in "the" and "this".

KAPPA is simply the K sound. It is usually transliterated with a "K", but occasionally with a "C". The letter "C" appears in the Roman alphabet, but not in the Greek, and its pronunciation in Latin seems to have changed from a "K" sound, to an "S" sound in some words.

LAMBDA is transliterated simply by "L".

MU is transliterated simply by "M".

NU is transliterated simply by "N".

XI is transliterated simply by "X".

OMICRON is transliterated by "O". It is best pronounced as the English short "O", as in "hot", "not" or "got".

PI is simply transliterated by "P".

SIGMA is simply translated as an "S".

TAU is simply transliterated as "T".

UPSILON is transliterated sometimes as "Y", and sometimes as "U". It is pronounced like the German "üaut;". It often appears in combination with other vowels. For example, EPSILON and UPSILON, (EU) in which we pronounce the two sounds. Many words borrowed from Greek have this combination, such as Europe, Eugenics, Euphoria, and in English this combination is pronounced like the word "you". When reading Greek, it is best to pronounce it as "E-OO". The combination OMICRON plus UPSILON (ou) is pronounced as "oo" as in the English "moon". OMICRON+UPSILON is sometimes transliterated as "OU" and sometimes as "U".

PHI is usually transliterated as "PH", but sometimes as "F". The Greek word PHANTASIA is at the origin of the English FANTASY, FANCY, FANTASTIC but also the more closely transliterated PHANTASM.

CHI is pronounced halfway between a K and an H (such as "CH" in the Scottish word "Loch"). It is usually transliterated as "CH", such as in CHORUS, CHRIST, CHARACTER.

PSI is pronounced usually as P+S, but in English we often shorten it to an "S". Examples are PSYCHE, PSYCHOLOGY, PSORIASIS.

OMEGA is pronounced as a long "O", such as in "HOPE". It is transliterated either simply by an "O", or else as an "O" with a special marking (Õ, Ó) to distinguish it from OMICRON.

The Iota subscript is a small IOTA written under another vowel. In classical times it probably indicated some difference in the pronunciation of the vowel, but today it is common to ignore it in pronunciation, although it plays a definite grammatical role in written language. It is not commonly transliterated.

The Rough Breathing Mark is transcribed as "H". All words beginning with vowels are preceded either by a smooth breathing mark (like a single end-quote) or a rough breating mark (like a single beginning-quote). When looking up a word in a greek dictionary, look for the vowel, and ignore the "H". For example, the English word "haptic" (related to touch) would be under the letter ALPHA. Some words derived from Greek that begin with this sound are HALO, HAMARTIA, HELIX, HELICOPTER, HEURISTIC, HOLISTIC (and WHOLE).