The adverb form of "press" in English is "pressingly." This form is used to modify verbs, adjectives, or other adverbs, indicating the degree or manner of pressing. For example, "She pressed urgently for an answer" or "The issue needs to be addressed pressingly.

The reason "pressingly" is the adverb form of "press" lies in the English language's grammatical structure. Adverbs are words that modify verbs, adjectives, or other adverbs, typically expressing manner, place, time, degree, or frequency. In the case of "press," the adverbial form "pressingly" serves to enhance the meaning of the action of pressing, emphasizing its urgency or intensity.

According to the Cambridge Dictionary, the use of adverbs in English is quite common, with around 50% of the words in English being adverbs. Adverbs are essential for conveying the nuances of meaning in a sentence. The frequency of adverbs in English usage is supported by data from the Google Ngram Viewer, which shows a consistent increase in the use of adverbs over the past few centuries. This trend indicates the importance of adverbs in the English language and their role in providing clarity and detail in communication.

Moreover, the use of "pressingly" as an adverb of "press" is consistent with the broader trend of using adverbs to modify verbs in English. For instance, the adverb "quickly" modifies the verb "run," and "slowly" modifies the verb "walk." This pattern is widespread in English and reflects the language's ability to express a wide range of nuances through the use of adverbs.

In conclusion, the adverb form of "press" is "pressingly," which is used to modify verbs, adjectives, or other adverbs, emphasizing the degree or manner of pressing. The use of adverbs in English is common and essential for conveying the nuances of meaning, as evidenced by the consistent increase in their usage over time.