Videon bevisar att trummisen var här.

Video is an en-word in Swedish: en video. In the singular definite form, Swedish usually adds the definite ending to the noun itself instead of using a separate word like the.

So:

• en video = a video
• videon = the video

Because video already ends in a vowel, the definite ending is just -n, not a full -en in spelling.

Trummisen is the singular definite form of trummis.

• en trummis = a drummer
• trummisen = the drummer

Again, Swedish puts the definiteness on the end of the noun. So instead of the drummer, Swedish uses trummisen.

Yes. Trummis is a very common everyday word for drummer. It is slightly informal or conversational, but completely normal.

A more formal or literal word is trumslagare, but in modern everyday Swedish, trummis is extremely common.

In Swedish, the definite article is often attached to the noun as a suffix.

So instead of saying:

• the video
• the drummer

Swedish says:

• videon
• trummisen

That is one of the biggest differences from English. In this sentence, both nouns are definite, so both get definite endings.

Att means that here. It introduces a subordinate clause:

• Videon bevisar = The video proves
• att trummisen var här = that the drummer was here

In English, that can sometimes be omitted, but in Swedish att is very commonly kept in sentences like this, especially in writing.

Var is the past tense of är / vara.

• är = is / are
• var = was / were

So:

• trummisen är här = the drummer is here
• trummisen var här = the drummer was here

Swedish verbs do not change for person the way English verbs do. The same var works for I, you, he, they, and so on.

After att, Swedish uses normal subordinate clause word order: subject + verb + other information.

So:

• att trummisen var här

not

• att var trummisen här

The version with the verb first would sound like a question pattern in Swedish. After att, you normally keep the subject before the verb.

Här means here in the sense of location:

• Trummisen var här = The drummer was here

By contrast, hit means to here, showing direction or movement toward this place:

• Trummisen kom hit = The drummer came here

So:

• här = location
• hit = direction toward the speaker

Yes, you could. That would mean The video proves that the drummer has been here.

The difference is:

• var här = simple past, was here
• har varit här = present perfect, has been here

In many situations, both are possible, but they are not exactly the same. Var här sounds more like a finished past situation, while har varit här connects the past event more directly to the present.