Iyán is an ANG demonstrative pronoun that refers to specific people, things or places that are near or close to the speaker (but may physically be unreachable). It is the Filipino translation of the word "that".
Shortening the linking verb ay drops the letter n in the word iyán (iya'y). This is done to connect the linking verb to the last vowel of the preceding word.
For a more formal approach, iyán can be used at the beginning of the of the sentence for the subject-predicate sentence word order and is followed by the linking verb ay (Iyán ay). The inverted sentence form, wherein iyán is placed at the end of the sentence, is more suitable for casual conversations. Ay is dropped in the inverted sentence form.
The shortened form of iyán is `yan. Letter "i" is dropped and an apostrophe is added before the letter "y". This is often done for a more casual feel. Either the subject-predicate sentence word order or the inverted sentence form can be used.