"The wife has an aged husband."
Translation:Uxor maritum senilem habet.
That's a feature of 3rd declension adjectives (the common type of which is listed: -is, -is, -e , showing that both masc and fem nominative singular ends in -is, and the neuter in -e).
Notice that 3rd decl. nouns also have identical endings for masculine and feminine: pater, patrem, patre and māter, mātrem, mātre , for "father" and "mother" (in the nominative, accusative, and ablative singular forms, respectively).
“vetum” assumes that “vetus” is second declension. vetus is actually third declension, as inconcinna has stated, and we have to obey the third declension rules. The stem of “vetus” is “veter”, to which is added third declension endings, except in the nominative singular, where all genders in this instance are “vetus”, and the neuter singular accusative, which is also “vetus”.
uxōrem is used when you want "the wife" to be a "her": that is, an object, in the accusative case (used for direct object of the verb, as in "The husband sees/greets/praises/leads the wife ", and for objects of some prepositions, like "The friends come towards the wife" = ad uxōrem ).
In this sentence, "the wife" is the one who has a husband; i.e., she is the subject of the verb ("has"), and is therefore nominative ( = uxor) in this sentence.
In this sentence, the aged husband is a HIM: in other words, an object.
"SHE has HIM."
The wife is the subject of "has", so she's in the nominative case.
The husband is the direct object of "has," so he's in the accusative case.
The accusative (masc/femin) form of a 3rd-declension adjective like senīlis is senīlem .
The adjective "old, aged" belongs to the third declension: you can tell from the way it is listed, with the endings -is, -is, -e (for the 3 nominatives singular, M/F/N).
It's senīlis, -is, -e , and its 3rd declension (M/F) accusative singular ending is: -em.
Only an "us, a, um" adjective (like magnus, a, um , "big, great") would have a -um accusative (masc) singular ending.
It definitely does! It's far more fluid than English for certain, but there are preferred word orders which in certain sentences can dictate where things have to go. For instance, when asking a yes or no question, the verb will virtually always be first. In other scenarios, the verb will usually be at the end of the clause to which it refers, as the general rule of thumb is SOV for word order.