INN stems employ the first definition, while under the more common alternative they would be described as roots. Pharmacology and pharmacotherapy (like health care generally) are universally relevant around the world, making translingual communication about them an important goal. An interlingual perspective is thus useful in drug nomenclature. The WHO issues INNs in English, Latin, French, Russian, Spanish, Arabic, and Chinese. A drug's INNs are often cognates across most or all of the languages, but they also allow small inflectional, diacritic, and transliterational differences that are usually transparent and trivial for nonspeakers (as is true of most international scientific vocabulary). For example, although "paracetamolum" (la) has an inflectional difference from "paracetamol" (en), and although "paracétamol" (fr) has a diacritic difference, the differences are trivial; users can easily recognize the "same word" (although Americans, who make up the majority of the world's native English speakers, will likely not recognize the word paracetamol in the first place, because that medicine is known as "acetaminophen" in the United States, even among most healthcare professionals, illustrating that the INN system is not perfect in its functioning). And although "парацетамол" (ru) and "paracetamol" (en) have a transliterational difference, they sound similar, and for Russian speakers who can recognize Latin script or English speakers who can recognize Cyrillic script, they look similar; users can recognize the "same word". Thus INNs make medicines bought anywhere in the world as easily identifiable as possible to people who do not speak that language. Notably, the "same word" principle allows health professionals and patients who do not speak the same language to communicate to some degree and to avoid potentially life-threatening confusions from drug interactions. A number of spelling changes are made to British Approved Names and other older nonproprietary names with an eye toward interlingual standardization of pronunciation across major languages. Thus a predictable spelling system, approximating phonemic orthography, is used, as follows:   Many drugs are supplied as salts, with a cation and an anion. The way the INN system handles these is explained by the WHO at its "Guidance on INN" webpage. For example, amfetamine and oxacillin are INNs, whereas various salts of these compounds – e.g., "amfetamine sulfate" and "oxacillin sodium" – are modified INNs (INNM).