Esperanto: A Complete and Comprehensive Grammar/Contractions for poetry

Contractions for Poetry
The final "-o" of a nominative noun may be replaced with an apostrophe. This is called elision (elizono).

The "-a" in the definite article la is also replaced in the same way and becomes l'. This is the only word other than nouns that can be used in this way.

The stress then falls on the last syllable of the word, not the penultimate one. Pierre Janton notes that this can be used to change the scansion of a line of poetry, e.g., from trochaic to iambic.

Elision can only be applied to nouns in the singular nominative case and the word la when preceded by a word ending in a vowel. For clarity, this cannot apply to adjectives or adverbs. Thus l' bona knabo, la bona knab '  and l' bona knab' are all theoretically possible, but it is impermissible to say la bon' knabo.