È aa is usually added to the last element in a sentence, but it can be used elsewhere, to focus on a particular element other than the general truth value of the sentence.
The usual rules about retention and deletion of final vowels and consonants apply with the use of È -aa. That is, final Ë -u is deleted from all nouns (for exceptions, see the section on Noun sandhi, § 1.311) before the addition of È -aa, as in the first sentence above. Other vowels are retained and glides ² y and  v are inserted according to the usual rules: ² y after i and e;  v after Ì uu, Ñ o and È aa (other vowel sequences do not occur.)