The following list of commonly confused words and tricky spelling rules draw directly from the sources cited below.
In British English and at UT, 'programme' is the prefered spelling when referring to a schedule of events.
In British English and at UT, 'program' is used for computer applications only.
Note also:
In American English 'program' is the preferred spelling for both uses above, so do realise that you will continue to notice this spelling in texts written in American English.
'Among' is used for undifferentiated items.
'Between' is used with individual, named items.
'Mutual' is used when more than one person has the same feeling/opinion as another towards a third party/object/concept etc.
'Reciprocal' is used when two or more people feel, think or act in the same way about or to one another.
'Less' is used with nouns which are not countable objects: if you could use much to describe having a lot of the noun, use 'less'.
'Fewer' is used with countable objects: if you could use many to describe having a lot of the noun, use 'fewer'.
'Effect' as a verb means to bring about, or to have the result that.
'Affect' as a verb means to have an impact on or to change something; it also means to simulate something which is untrue.
'Effect' as a noun means the impact something causes.
'Affect' as a noun means someone’s outward appearance of their psychological state.
'Infer' is to read a meaning into a statement which has not been explicitly stated: to read between the lines.
'Imply' is to suggest something without explicitly stating it: to hint at something (usually something negative).
Comparing something to another thing highlights a (perhaps metaphorical) similarity
Comparing something with another thing highlights the differences between them
The two-word usage of 'all together' means, in a body or in a group.
The joined up one-word usage of 'altogether' is used as an adverb, meaning completely, or entirely.
European Commission English Style Guide - A handbook for authors and translators in the European Commission Eighth edition: January 2016. Last updated: July 2023 "[PDF File]" https://commission.europa.eu/system/files/2023-07/styleguide_english_dgt_en.pdf
University of Oxford Style Guide. "[PDF File]" Retrieved from https://www.ox.ac.uk/public-affairs/style-guide?wssl=
Oxford Learner's Dictionary. Retrieved from https://www.oxfordlearnersdictionaries.com/definition/academic/programme1