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A language may spell some words with unpronounced letters that exist for historical or other reasons. For example, the spelling of the Thai word for "beer" [เบียร์] retains a letter for the final consonant "r" present in the English word it was borrowed from, but silences it. |
Pronunciation of individual words may change according to the presence of surrounding words in a sentence (sandhi). |
Different dialects of a language may use different phonemes for the same word. |
A language may use different sets of symbols or different rules for distinct sets of vocabulary items, such as the Japanese hiragana and katakana syllabaries, or the various rules in English for spelling words from Latin and Greek, or the original Germanic vocabulary. |
National languages sometimes elect to address the problem of dialects by simply associating the alphabet with the national standard. Some national languages like Finnish, Armenian, Turkish, Russian, Serbo-Croatian (Serbian, Croatian and Bosnian) and Bulgarian have a very regular spelling system with a nearly one-to-one... |
At the other extreme are languages such as English, where the pronunciations of many words simply have to be memorized as they do not correspond to the spelling in a consistent way. For English, this is partly because the Great Vowel Shift occurred after the orthography was established, and because English has acquired... |
Sometimes, countries have the written language undergo a spelling reform to realign the writing with the contemporary spoken language. These can range from simple spelling changes and word forms to switching the entire writing system itself, as when Turkey switched from the Arabic alphabet to a Latin-based Turkish alph... |
The standard system of symbols used by linguists to represent sounds in any language, independently of orthography, is called the International Phonetic Alphabet. |
See also |
A Is For Aardvark |
Abecedarium |
Acrophony |
Akshara |
Alphabet book |
Alphabet effect |
Alphabet song |
Alphabetical order |
Butterfly Alphabet |
Character encoding |
Constructed script |
Cyrillic |
English alphabet |
Hangul |
ICAO (NATO) spelling alphabet |
Lipogram |
List of writing systems |
Pangram |
Thai script |
Thoth |
Transliteration |
Unicode |
References |
Bibliography |
Overview of modern and some ancient writing systems. |
Chapter 3 traces and summarizes the invention of alphabetic writing. |
Chapter 4 traces the invention of writing |
External links |
The Origins of abc |
"Language, Writing and Alphabet: An Interview with Christophe Rico", Damqātum 3 (2007) |
Michael Everson's Alphabets of Europe |
Evolution of alphabets, animation by Prof. Robert Fradkin at the University of Maryland |
How the Alphabet Was Born from Hieroglyphs—Biblical Archaeology Review |
An Early Hellenic Alphabet |
Museum of the Alphabet |
The Alphabet, BBC Radio 4 discussion with Eleanor Robson, Alan Millard and Rosalind Thomas (In Our Time, 18 Dec. 2003) |
Orthography The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equa... |
The sum of the atomic number Z and the number of neutrons N gives the mass number A of an atom. Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes) and the mass defect of nucleon binding is always small compared to the nucleon mass, the atomic mass... |
Atoms with the same atomic number but different neutron numbers, and hence different mass numbers, are known as isotopes. A little more than three-quarters of naturally occurring elements exist as a mixture of isotopes (see monoisotopic elements), and the average isotopic mass of an isotopic mixture for an element (cal... |
The conventional symbol Z comes from the German word 'number', which, before the modern synthesis of ideas from chemistry and physics, merely denoted an element's numerical place in the periodic table, whose order was then approximately, but not completely, consistent with the order of the elements by atomic weights. ... |
History |
The periodic table and a natural number for each element |
Loosely speaking, the existence or construction of a periodic table of elements creates an ordering of the elements, and so they can be numbered in order. |
Dmitri Mendeleev claimed that he arranged his first periodic tables (first published on March 6, 1869) in order of atomic weight ("Atomgewicht"). However, in consideration of the elements' observed chemical properties, he changed the order slightly and placed tellurium (atomic weight 127.6) ahead of iodine (atomic weig... |
A simple numbering based on periodic table position was never entirely satisfactory, however. Besides the case of iodine and tellurium, later several other pairs of elements (such as argon and potassium, cobalt and nickel) were known to have nearly identical or reversed atomic weights, thus requiring their placement in... |
The Rutherford-Bohr model and van den Broek |
In 1911, Ernest Rutherford gave a model of the atom in which a central nucleus held most of the atom's mass and a positive charge which, in units of the electron's charge, was to be approximately equal to half of the atom's atomic weight, expressed in numbers of hydrogen atoms. This central charge would thus be approxi... |
Moseley's 1913 experiment |
The experimental position improved dramatically after research by Henry Moseley in 1913. Moseley, after discussions with Bohr who was at the same lab (and who had used Van den Broek's hypothesis in his Bohr model of the atom), decided to test Van den Broek's and Bohr's hypothesis directly, by seeing if spectral lines e... |
To do this, Moseley measured the wavelengths of the innermost photon transitions (K and L lines) produced by the elements from aluminum (Z = 13) to gold (Z = 79) used as a series of movable anodic targets inside an x-ray tube. The square root of the frequency of these photons increased from one target to the next in a... |
Missing elements |
After Moseley's death in 1915, the atomic numbers of all known elements from hydrogen to uranium (Z = 92) were examined by his method. There were seven elements (with Z < 92) which were not found and therefore identified as still undiscovered, corresponding to atomic numbers 43, 61, 72, 75, 85, 87 and 91. From 1918 to ... |
The proton and the idea of nuclear electrons |
In 1915, the reason for nuclear charge being quantized in units of Z, which were now recognized to be the same as the element number, was not understood. An old idea called Prout's hypothesis had postulated that the elements were all made of residues (or "protyles") of the lightest element hydrogen, which in the Bohr-R... |
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