'Not attempt to find things about outside' is concerning, but workable.

"Very well. We will dial again next day."

The guards stand there warily until the thing closes.

It does indeed close!

And, the next day, opens up again.

"We are ready to send a party through. Have you been able to locate a working DHD, or should we bring our equipment?"

The tunnel has been renovated! Somewhat. The walls and floor are smooth now, the dust and malaise in the air is gone, it's pleasantly warm instead of dreadfully chilly, all the rusty fortifications have been moved back some to allow a sturdy wooden table with plenty of plain wooden chairs on both sides to sit a few meters in front of the gate. There are metal standing lamps illuminating everything, without any cords.

A very tired looking middle-aged man in a brown and black military uniform is sitting at the table, as well as a younger man in a nicer vest-and-jacket sort of thing. There's also a young woman in a simple dress, with a rough notepad and a pencil.

"We have no means of returning you."

"Alright, we are coming through."

And a party of five will come through. In front, a woman, clearly a civilian.

A man, visibly military, though not carrying a weapon right now.

A man with a look of extreme arrogance, holding a small device in his hands.

A woman, less clearly identifiable.

And a man who looks like he can wrestle five people at a time, carrying a black plastic case.

"My name is Dr. Elizabeth Weir, and this is Lt. Col. John Sheppard, Dr. Rodney McKay, Teyla Emmagan, and Ronon Dex. I welcome you on behalf of my people."

The woman starts writing.

"I am Major Tresso Valdir," the military uniformed man says. "To my left is Mr. Ernest Udaloy, a representative of the interests of Chelska. To my right is Mrs. Casso Agonosila, she is..." He frowns. "...Meeting writer. She will write what we say, for reference."

"Hello!" Ernest Udaloy smiles and stands to perform a short bow. "We are pleased to make peaceful contact with another nation, even in an unexpected way. While we have reservations, we have great hopes for this meeting as well. It is unfortunate that this language is an invitation to discord."

"We are pleased as well." She will mirror the bow, and take one of the chairs, with the rest of the party following.

"May I inquire, what is troubling with the language? So far we've observed it to be a common language in most of the galaxy, which is surprising in itself, but it appears it has some additional baggage here?"

"It is the language of the Glittering Meadow, those that proclaim themselves lords of all. They are responsible for wars and atrocities. We have numerous disagreements."

"Huh. What is your language then? Perhaps it will be familiar to me, and may be useful if your people are discomforted by English."

"Chelskan. Named for the... Land area, more than the nation we have formed in it."

He proceeds to speak several generic sentences. It sounds... Sort of like a weird patois pidgin of Greek and a lot of random other Slavic-family languages? With a bit of Arabic, maybe.

She's fluent in Russian and Arabic, knows a fair bit of Greek. Can she understand it? Speak it?

She can mostly-sort of understand it. He's saying things like 'this is an example sentence' and talking about breakfast (potato soup). But there's a lot of potential for misinterpretations. Speaking it would be pretty ugly.

"Thank you. It is similar to some of the languages I know, and while I don't think I could speak it just from that similarity, I look forward to learning it properly."

This is very unlikely to be complicated Wraith or Genii plot by now, faking a language really doesn't sound like either of them.

"Let us begin then. I am from a planet called Earth, which is located in another galaxy, and I am the leader of an expedition, sent to explore this galaxy and make contact with the people here. We posses considerable technology, but limited resources. I believe we can establish mutually beneficials relashionships between our people."

"We do have resources. And you do have interesting technology. However for now I believe we should get to know each other, our priorities, our goals... Do you represent all of Earth? We represent the people of the Chalk Valley and surrounding mountains. The Chelskan Common Union is formed to serve the people."

"I represent Atlantis Expedition, which is under the oversight of international committee, containing representatives from most nations of Earth." 

"Exploration, you say? And yet you mentioned Resources almost immediately. These first moments are the most difficult, especially when we have no other way to learn more."

"Yes. Our expedition does have a strategic objective as well, but revealing everything so early would be unwise. If you are worried about us subjugating other people, I can assure you that we possess neither the intention nor capacity to do so. We can discuss what we can do to proove our intentions to your satisfaction."

"That is our primary worry, yes. We must be cautious. The world has not been kind to Chelska in recent years. I would see what proof you would offer without specific request?"

"Proving a negative is hard. We can give some of your people a tour of our city, and some of the planets we are in contact with. We can provide you with some defensive technology, though we will need to know more of your world before giving anything that can be used offensively. We can outline the current situation in the galaxy, and while you won't be able to independently verify it until you can use the stargate yourself, you can see whether it fits together."