(The question was asked here but the answers didn't really address what I am about to ask.) One rule about long vowels is that the long vowel for え段 is written え段 + い. For instance けいじどうしゃ is pronounced as ケージドーシャ, not ke-i-ji-do-u-sha.
What about the ている pattern for verbs, as in 知っている? Is it te-i-ru or te-e-ru?