the late 19th century. In 1957, it was standardized on Cyrillic, and in 1996, a Gagauz alphabet based on Latin characters was adopted (derived from the Turkish alphabet). Surguch, a Turkic language, was spoken by a small group of Orthodox Christians in northern Greece. It is now written in Latin or Cyrillic characters. Urum or Greek Tatar, spoken by Orthodox Christians, used the Greek alphabet. Judaeo-Spanish or Ladino, a Jewish dialect of Spanish, has occasionally been published in Greek characters in Greece. The Italian humanist Giovan Giorgio Trissino tried to add some Greek letters (Ɛ ε, Ꞷ ω) to Italian orthography in 1524. In mathematics and science Greek symbols are used as symbols in mathematics, physics and other sciences. Many symbols have traditional uses, such as lower case epsilon (ε) for an arbitrarily small positive number, lower case pi (π) for the ratio of the circumference of a circle to its diameter, capital sigma (Σ) for summation, and lower case sigma (σ) for standard deviation. Formerly, the Greek letters were used for naming North Atlantic hurricanes if the normal list ran out. This happened only in the 2005 and 2020 hurricane seasons for a total of 15 storms, the last one being Hurricane Iota. In May 2021 the World Health Organization announced that the variants of SARS-CoV-2 of the virus would be named using letters of the Greek alphabet to avoid stigma and simplify communications for non-scientific audiences. Astronomy Greek letters are used to denote the brighter stars within each of the eighty-eight constellations. In most constellations, the brightest star is designated Alpha and the next brightest Beta etc. For example, the brightest star in the constellation of Centaurus is known as Alpha Centauri. For historical reasons, the Greek designations of some constellations begin with a lower ranked letter. International Phonetic Alphabet Several Greek letters are used as phonetic symbols in the International Phonetic Alphabet (IPA). Several of them denote fricative consonants; the rest stand for variants of vowel sounds. The glyph shapes used for these letters in specialized phonetic fonts is sometimes slightly different from the conventional shapes in Greek typography proper, with glyphs typically being more upright and using serifs, to make them conform more with the typographical character of other, Latin-based letters in the phonetic alphabet. Nevertheless, in the Unicode encoding standard, the following three phonetic symbols are considered the same characters as the corresponding Greek letters