Publications Office – Interinstitutional Style Guide

10.3.1. Conventions
10.3.2. Tricky plurals
10.3.3. Interference effects and in-house words, expressions and constructions

10.3. Spelling

10.3.1. Conventions

(a)

English spelling. Follow the standard usage of Britain and Ireland.

As a general rule, the first spelling given on Oxford’s English dictionary on Lexico should be followed. An exception to this rule is the spelling of ‘-iz-’ words (see below).

(b)

-is-/-iz- spelling. Use the -is- spelling. Both spellings are correct, but this rule is to be followed for the sake of consistency in EU texts.

(c)

Note, however, that the names of bodies in other English-speaking countries retain the original spellings, e.g. US Department of Defense, Australian Labor Party. For international organisations, follow their own practice, e.g. World Health Organization. Follow the list in Annex 1 to the English Style Guide.

(d)

The -yse form is the only correct spelling for words such as paralyse and analyse.

(e)

When adding -able, drop a final silent -e at the end of the stem (debate – debatable, conceive – conceivable) unless it would change the pronunciation of the preceding consonant (changeable, traceable); the only common exceptions are sizeable and saleable (sizable and salable are US spellings).

(f)

Double consonants. Follow the convention of doubling a final -l after a short vowel on adding -ing or -ed to verbs (sole exception: parallel, paralleled) and adding -er to make nouns from verbs:

level, levelling, levelled, leveller
travel, travelling, travelled, traveller

Other consonants double only if the last syllable of the root verb is stressed or carries a strong secondary stress:

admit, admitting, admitted
format, formatting, formatted
refer, referring, referred

but

benefit, benefiting, benefited
combat, combating, combated
focus, focusing, focused
target, targeting, targeted

Exception: a few verbs ending in -p (e.g. handicapped, kidnapped, worshipped, but not developed).

(g)

Judg[e]ment. Judgment is used in legal contexts, judgement in all other contexts.

(h)

Data-processing usage. Avoid the forms ‘input(t)ed’ and ‘output(t)ed’. Instead, use ‘input’ and ‘output’: e.g. ‘70 000 items of data were input last month’. However, note the verb ‘to format’ which takes the forms ‘formatted’ and ‘formatting’.

(i)

Accents and diacritics in personal names should be reproduced.

10.3.2. Tricky plurals

Follow the list below:

Singular	Plural
addendum	addenda
appendix	appendices (books) appendixes (anatomy)
bacterium	bacteria
bureau	bureaux
consortium	consortia
corrigendum	corrigenda
criterion	criteria
curriculum	curricula
embargo	embargoes
focus	foci (mathematics, science) focuses (other contexts)
formula	formulae (science) formulas (politics)
forum	forums (fora only in relation to ancient Rome)
genus	genera
index	indexes (books) indices (science, economics)
maximum	maxima (mathematics, science) maximums (other contexts)
medium	media (press, communications, IT) mediums (life sciences, art)
memorandum	memorandums or memoranda
minimum	minima (mathematics, science) minimums (other contexts)
moratorium	moratoriums or moratoria
papyrus	papyri or papyruses
phenomenon	phenomena
plus	pluses
premium	premiums
referendum	referendums or referenda
spectrum	spectra (science) spectrums (politics)
symposium	symposiums or symposia
vortex	vortices

10.3.3. Interference effects and in-house words, expressions and constructions

Especially in texts intended for the general public, care should be taken to avoid interference effects and the use of in-house words, expressions, constructions and meanings that are not generally recognised outside the EU institutions. Many of these are the result of confusion between English words and those from other languages (particularly French).

Frequently misused term	Alternative
according to	in accordance with
adequate	appropriate
(legal) base	(legal) basis
coherent	consistent
debriefed	briefed or informed
define	establish or lay down
detached	seconded
different	various
disincentivise	discourage
dispose of	have
ensure	provide for
foresee	envisage or provide for
guarantee	ensure
in case	if
in case of	in the case/event of
incentivise	encourage
incite	encourage
modalities	detailed arrangements
modify	amend
modulation	reduction
nominate	appoint
planification	planning
precise	specify
retain	select

Please also see sections 2.14 and 2.15 of the English Style Guide, How to write clearly and Claire’s Clear Writing Tips (for links, see Section 11, Reference works).