Lesson 27 Latin and Greek Plurals

crisis	crises
basis	bases
oasis	oases
diagnosis	diagnoses
analysis	analyses
stimulus	stimuli
alumnus	alumni
radius	radii	(radiuses)
curriculum	curricula	(curriculums)
criterion	criteria	(criterions)
index	indexes	(indices)
appendix	appendixes	(appendices)
octopus	octopuses	(octopi)
aquarium	aquariums	(aquaria)
stadium	stadiums	(stadia)
vacuum	vacuums	(vacua)
memorandum	memorandums	(memoranda)
(datum)	data
medium	media	(medias)
(agendum)	agenda	agendas

1.	The singular forms of the first five words end with sis. How is the spelling changed to form the plurals of these words? ____________________________________________________________________________
2.	The plurals of the next five words are formed by changing the last two letters of the singular form. Are the plural forms longer or shorter? __________________________________________________
3.	The word forms in parentheses are shown in the dictionary, but they are not the preferred spellings. Are the preferred plurals for the words in the first column English or foreign? __________ Are the preferred plurals of the first seven words in the second column English or foreign? __________
4.	Some forms of the last three words are in parentheses because they are not commonly used. Which of the three Latin plurals is often used as both the singular and plural forms? __________

Lesson Generalization Some words still use only the Latin or Greek plural forms. A few of these have an alternative English plural. For other words, the English plural form is preferred. Because these kinds of language changes are gradual, older dictionaries may have different information than more recent dictionaries. Common usage has almost eliminated the Latin singular of some words, such as datum and agendum. Mnemonic device: Latin singular forms are usually longer than plural forms.

© McDougal Littell Inc.

Grade 8 Spelling SkillBuilders