The essential characteristic meaning of "tilî" is the shrill sound of it. It is, therefore, normally just used to describe a child's or a woman's scream. For men, we would use "sigaw" (shout) instead. If you'd use "tilî" for a man, it's like saying he's a sissy and if a man uses it to describe his own reaction, it might suggest that he's coming out in a subtle way. 😀
Common verb forms:
tumilî = to shriek (subject/actor-focused) - tumilî, tumitilî, titilî
magtílian = to shriek as a group (subject/actor-focused) - nagtílian, nagtítilian, magtítilian
tilián = to shriek at someone/something (object-focused) - tinilián, tinítilián, títilián
mágtitilî = to keep on screaming (subject-focused) - nágtitilî, nagtítitilî, magtítitilî (note that there are 3 "ti"s in the present and future tenses)
"Huwag kang tumilî!" = Don't scream!/Stop screaming! (for women and children)
"Huwag kang sumigáw!" = Don't shout!/Stop shouting! (for men)
"Laging tumitilî si Alice pag/kapag nakakakita ng dagâ" = Alice always squeals whenever she sees a rat.
"Nagtílian ang mga fans ni Madonna nang nakita siya" = Madonna's fans screamed when they saw her. (It is OK to use "nagtílian" in this case even if there were men in the group because the sound produced would most likely be shrill anyway. "Nagsígawan" (shouted) would also be acceptable, but it would suggest that the sound was lower in pitch than what's typical on such occasions).
"Siguradong títilián si Madonna ng mga fans niya kapag/pag nakita siya" = For sure Madonna's fans will scream (at her) once/when they see her.
"Ano ka ba? Nagtítitilî/Tumitilî ka na diyan kahit hindi pa umaandar itong roller coaster" = What's wrong with you? You're already screaming there even if this roller coaster hasn't moved yet.
"tílian" is a plural form of the noun "tilî".
"Ang tílian ng mga tao sa loób ng sine ay diníg hanggáng sa labas" = "Ang mga tilî ng tao /Ang tilî ng mga tao sa loób ng síne/sinehán ay diníg hanggáng sa labás" = The scream/screaming of the people inside the theater can be heard all the way outside.