Ttyjukl

Russians and Americans are competing to make an alliance with an alien race that lives on a planet with a very thick atmosphere. Most of the plant life on the planet lives hanging in the air from gas bags. Because it is so easy to fly, the natives have developed very primitive aircraft. The Russians have sophisticated linguists who are trying to establish communication. The hero, an American, knows nothing about linguistics, but does know a thing or two about flying. He teaches the natives about the concept of a rudder, and they are so thankful they form an alliance with the Americans. The hero explains that having something to say is more important than how you say it.

I thought it was by Eric Frank Russell, but can't find it in his work. It was probably written in the 1950's or early 1960's.

"Something to Say", a novelette by John Berryman, also the (unaccepted) answer to this other question; published in Analog Science Fiction & Science Fact, August 1966 and reprinted in the anthology Analog 6. Here is an Amazon customer review:

Carina VI has been identified as having an intelligent population. The Federation intends to make contact following due careful procedure, but the competing blocs on Earth are seeking to get ahead of each other in this process.

Russians and Americans are competing to make an alliance with an alien race

One Bloc or the other is getting desperate," he said bitterly. He paused to light his smoke. "Somebody made an illegal landing during the last watch."

"On Carina VI?" I asked, startled.

"No. Here on Six Beta. Oh, it's plain enough what's on their mind. Whether it's the Dembloc or the Sovbloc I don't know, but one Bloc has decided the only way to get preference on Six is to land some contrabands on the planet before the Federation opens it up under the Treaty. With only a standard month left before we make our first landing, they have very little time. Obviously, they can't land a deep-space vehicle there without a grid, so they've got the hot idea of stealing one of our atmospheric probes."

that lives on a planet with a very thick atmosphere.

"This is one tremendously deep atmosphere. At the surface, pressures are about six times standard. But the oxygen percentage is only one sixth of standard. While that makes it breathable on the surface, way up here, at a quarter standard pressure, there isn't enough equivalent oxygen to keep a flea alive."

Most of the plant life on the planet lives hanging in the air from gas bags.

And above us, I suddenly realized, lay the forest. In the thick air, perhaps a couple thousand meters high, floated amorphous shapes, apparently equally made of large bladders, nearly transparent in the morning light, and fibrous strands holding them together. There was a good deal of greenery strung around the strands. They obviously had been the source of the rending thumps shortly before we crashed.

"What are they?" Diane demanded, pointing up.

"Flying trees, I guess," I said. "With this thick an atmosphere, a lot of things are possible. I'm guessing that by some inverted photosynthesis those plants separate hydrogen from water and secrete it in those great big bladders. As the sun comes up and they heat, I imagine they climb to some pretty respectable heights."

Because it is so easy to fly, the natives have developed very primitive aircraft.

There was a pilot in each of the soaring things, sitting, lying, or standing, I had no way of knowing, in an open cockpit. He was steering his glider with what appeared to be two hands, and his upper end—if that's what we were looking at—was shockingly human.

Bird-like, or airplane-like, the stubby-winged gliders made a series of rough, slipping turns in a pattern and prepared to land single-file forty or fifty meters from where we sat in the bracken. As they flared out "over the fence" they wobbled in near-stalls, accentuated by the extremely low aspect ratio of their wings. At the comical last moment, the "landing gear" was extended. Just two of the most human-looking legs and feet you ever saw. Each pilot trotted a few steps and squatted down, grounding his glider.

The Russians have sophisticated linguists who are trying to establish communication

I laughed, backing away from her aggressive advance across the stone floor. A little common sense started percolating through my thick head. Our interests were adverse. She had landed on Six to grease the way for the Sovbloc, in violation of the Interplanetary Treaty. The mission I was part of on Six Beta had been recruited to prevent either Bloc from getting a preferred position.

"You want to know too much," I said, continuing to chuckle. "It's time I clammed up."

She shrugged, ramming her fists onto her hips, her feet apart. "You won't talk, eh? So I'll ask them." She sounded pretty smug.

I let defeat sound in my voice. "You mean you can talk with them already?" I wanted to know.

[. . . .]

"The advantage of being a trained linguist," Diane told me. "And just to cheer you a little, L. C. Reamy, you might as well know that Sixian is a positional speech, like Chinese. But unlike Chinese, it is inflected about as much as Sanskrit."

The hero, an American, knows nothing about linguistics, but does know a thing or two about flying. He teaches the natives about the concept of a rudder,

On the opposite wall I drew with much more care. Here I laid out a better mousetrap. The improvement on their glider featured some very simple ideas. In the first place, I put some dihedral in the wings. Secondly, I increased the aspect ratio, so that span was about five times root chord, while sticking to their essentially correct idea of an elliptical plan-form. My biggest change, although only the engineering-minded would catch it, was in the empennage. I drew control horns on the rudder similar to those the natives had used to flex the stabilizer.

and they are so thankful they form an alliance with the Americans. The hero explains that having something to say is more important than how you say it.

The chief shook his head. "I can't understand it," he said to her. "Here you are, a prize linguist, able to talk a blue streak with the locals. And here's Reamy, making dumb-show with his hands. How does it occur that he has them in the palm of his hand, and you are still a captive?"

She shook her head. "I should have killed him when I had the chance!" she said.

"And you can't tell me how he did it?"

"No, I can't," she said angrily.

The chief turned back to me.

"She overlooked one thing," I grinned at him. "You have to have something to say."