Hello and welcome to the intelligence on Economist Radio.

I'm your host, Jason Palmer.

Every weekday, we provide a fresh perspective on the events shaping your world.

Congo is a country beset by decades-old conflicts, but in the middle of it all, there's striking natural beauty.

We visit a vast national park that's beefing up security, generating electricity, and providing new jobs in what should be a well-known tourist destination.

And it seems like some languages are just needlessly difficult.

All those cases and clauses and conditionals are, well, confusing.

We look into new research that sheds light on why languages grow and shrink.

But first...

As it recovered from the financial crisis, America began more than 10 years of economic growth.

But worrying signs, not least a bumpy week in the markets, have many concerned that the good times are coming

to an end. The returns on bonds held for a short time are higher than returns for holding them

for years. That inverted yield curve has in the past been a good predictor of a coming recession.

As growth slows and the uncertainty over trade tensions remains,

nervous investors are wondering if the next downturn is around the corner.

What we've seen in the markets this week is a kind of continuation of what we've seen in recent weeks,

a sort of growing anxiety about the global economy linked to America's

trade war with China. John O'Sullivan writes Buttonwood, our column on financial markets.

We've seen investors pushing even further into the safest sort of assets, so government bonds. In Europe, that means

that government bonds in Germany from overnight cash rates to 30 years, have now got negative

interest rates on them. In Switzerland, bonds right out to 50 years have got negative interest rates.

So there's a real pressure on and desire to own the safest kind of assets. The stock market

...