All the major style guides advise the writer to select a widely available reference work and to follow the spellings given in this work. Modern computer software allows dictionary and encyclopedia spellings to be reproduced exactly. Guidance that suggests dropping off technically difficult diacritics may be disregarded as outdated. Better known names, for example "Istanbul" or "Zurich," are often spelled without diacritics in English even though diacritics are part of the local language spelling. Lesser known names are generally spelled in the manner of the original language. Diacritics are not normally used for sports figures or for Vietnamese names. These are just rules of thumb, and each case should be checked separately in an appropriate reference work.
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All the major style guides advise the writer to select a widely available reference work and to follow the spellings given in this work. Modern computer software allows dictionary and encyclopedia spellings to be reproduced exactly. Better known names, for example "Istanbul" or "Zurich," are often spelled without diacritics in English even though diacritics are part of the local language spelling. Lesser known names are generally spelled in the manner of the original language. Diacritics are not normally used for sports figures or for Vietnamese names. These are just rules of thumb, and each case should be checked separately in an appropriate reference work.