Current English for 14 is fourteen but mathematically it is ten & four. Research on number sense, counting, arithmetic and the predictive value for later mathematical abilities tends to be methodologically invalid when it doesn't measure true number sense that can develop when the numbers are pronounced in mathematical proper fashion. Researchers can correct by including proper names in the research design, but this involves some choices, and when each research design adopts a different scheme, also differently across languages, then results become incomparable. A standard would be useful, both ISO for general principles and national implementations. Research may not have the time to wait for such (inter ) national consensus. This article suggests principles of design and implementations for said languages. This can support the awareness about the need for a process towards ISO and national consensus, and in the mean time provides a baseline for research.

(a) May 14 2018: The update is to use "&" as the connective of the place value positions. Thus also for higher positions as e.g. 657 = six·hundred & five·ten & seven. The ampersand better is 1 fontsize smaller than the other text. See the developed software and http://thomascool.eu/Papers/NiceNumbers/Index.html (b) June 28 2018: This research finds support at https://zwanzigeins.jetzt (c) August 20 2018: Better expression of the distinction between simplified 11 = ten & one for everyday use and non-simplified 11 = one.ten & one.one for clarification of the place value system. (d) September 14 2018: The hyphen is used for common expressions like twenty-one.