On behalf of this fossilised phrase is a recent article I wrote for Macmillan Dictionary Blog about the expression on behalf of:
On someone’s behalf, etymologically speaking, means ‘on someone’s side’, from an old meaning of half. It emerged in Middle English as a result of blending the two phrases on his halve and bihalve him, both of which meant ‘on [or by] his side’; thus Chaucer, ‘Spek thow thiself also to Troylus On my bihalve’. The word in modern use has two related meanings: 1. ‘instead of someone, or as a representative of someone’, and 2. ‘in order to help someone’. Sense 1 is more neutral, while sense 2 implies active support or defence of a person.
The post also looks at in behalf of and lesser known variants, transatlantic differences, the non-standard plural *on their behalves, and a recent development whereby on someone’s behalf is used to mean on someone’s part.
Is ‘invite’ acceptable as a noun? examines a disputed nominalisation, including its use in different registers and the criticism it has received from language authorities:
With another throw of the historical dice, invite as a noun might have developed as the norm, with invitation considered an inkhornish variant. But invitation got there first and established itself as the noun of choice. Flannery O’Connor and William Makepeace Thackeray both used invite as a noun – but in letters. When it appears in edited writing it quite often marks a light or jocular tone. It may even be framed by scare quotes to mark its less-than-wholly-proper stature.
But we can acknowledge all this without lambasting the word as a ‘needless barbarism’, as one critic did. Can we omit needless accusations of barbarity? That’s my invite to the critics.
Older posts may be found in my Macmillan Dictionary Blog archive.