It's just a full expression of the l. In English, we tend to cut short consonants at the ends of words, but in good classic Klingon pronunciation, the sound carries until the whole letter has been sounded. In addition, in English we often weaken unstressed syllables into a schwa. So when our English ears hear the sound of the consonant being carried out like that we conclude there must be an unstressed vowel there. But if there were a vowel, it should be expressed clearly and you should easily be able to identify which vowel it is.
The words would appear in the opposite order for that. val is a verb, but it is an adjectival verb, also called a verb of quality or a "be" verb - "to be smart". Like all other verbs, the subject of the verb comes after the verb. So when we place the noun jagh after the verb, it is acting as the subject, "The enemy is smart." Many verbs can take objects and when they do, the object is placed before the verb: jagh legh ("He sees the enemy"). These adjectival/quality/"be" verbs cannot take objects - you can't "smart something". When the noun is placed in what would normally be the object position before the verb (jagh val), it means that the verb is acting like an adjective to create a noun phrase ("the smart enemy"). This noun phrase can then be used as either the subject or object of a sentence: jagh val legh HoD 'ej HoD legh jagh val ("The captain sees the smart enemy and the smart enemy sees the captain").