To inflect a word means to change its spelling to make it mean something different. Inflected languages use those spelling changes (usually the ending of a word, AKA the suffix) to show how words relate to each other in a sentence (and consequently, what the sentence means). Non-inflected languages DON'T use spelling changes to change a word's or a sentence's meaning.
"But wait!" you cry. "English uses endings! It has -s and -ing and -ed! You use those all the time!"
And you're right, English does use those. But non-inflected languages (like English) use word order the way that inflected languages (like Latin) use spelling changes: change or remove it, and you've changed or removed the meaning.
Conversely, non-inflected languages don't use spelling changes very much -- and inflected languages don't use word order very much -- and so those will rarely change the meaning. (And even if it does change the meaning, it changes it LESS than changing the other thing.)
The pretty girls carried water.
a. The pretty girl carry water. (spelling change/removed endings)
b. Girls water carried pretty the. (word order change)
Option A still makes sense...mostly. You see one girl instead of multiple girls, and the carrying happens now instead of before now...but it's still the same basic idea, right? Whereas option B is gibberish. If you're fluent in English, you can GUESS that the writer meant "the pretty girls carried the water" (or "pretty girls carried the water"), but only because that's the only logical arrangement of those words.
In Latin, this example would be:
Puellae bellae aquam portāvērunt.
a. Bellae portāvērunt aquam puellae. (word order change)
b. Puella bella aqua portāre. (spelling change/removed endings)
Once again, option A still makes sense, because the inflected language cares about spelling and NOT word order. This sentence actually makes MORE sense than its English counterpart because English does use some inflections (spelling changes), whereas Latin does not care about word order.* Option B, however, is gibberish despite using the same word order as the original sentence.
What does this mean for a Latin student?
YOU HAVE TO TRANSLATE THE GRAMMAR AS WELL AS THE INDIVIDUAL WORDS. You have to know the grammar backwards and forwards -- in both languages! -- in order to translate accurately between them.
* Latin has a "common" word order...but because it doesn't actually affect meaning, authors can play with word order to emphasize relationships in their sentences. Want to say "the flower is in between the rocks"? You can say "the rocks the flower in between" and it still means the same thing, but now you have a pretty little word picture where the word for "flower" is in between the words for "in between" and "the rocks"...just like the meaning of the sentence!
Next Lesson: Declension and Conjugation | Latin Basics | Home Page