Learn Danish: Diagrammet viser at priserne stiger. - The chart shows that prices are rising.

Stiger is an intransitive verb, meaning the action happens on its own without a direct object (the prices themselves rise). If a company or a person is actively raising prices, you must use a transitive verb like hæver or sætter op (for example, De hæver priserne - They are raising the prices).

Shouldn't there be a comma before at in Danish?

It depends on the comma rules you follow! Under the traditional grammatical comma system, which most Danes still use, you would put a comma before the subordinate clause: Diagrammet viser, at priserne stiger. However, the official Danish Language Council also allows dropping this "start comma," which makes the sentence perfectly correct as written here.

How do you pronounce the 'g' in stiger?

It is pronounced as a "soft g" (blødt g), which in this position glides into an "i" or "y" sound. The word stiger rhymes exactly with piger (girls).

The translation says "are rising", but stiger is simple present. How do we form the continuous tense in Danish?

Danish does not have a direct grammatical equivalent to the English continuous "-ing" form. The simple present tense stiger translates to both "rise" and "are rising". If you specifically need to emphasize that the prices are in the process of going up right this moment, you could use the construction er ved at (e.g., priserne er ved at stige), but in a general statement like this, the simple present is completely natural.