He has trouble with the "r" sound.

Simple Definition: 
In colloquial terms, the Italian expression ” Ha la erre moscia” is commonly expressed as “he has trouble pronouncing the R sound”. It is an informal way to describe the condition of rhotacism, a speech impediment where a person has difficulty pronouncing the “R” sound correctly. In more formal language, we can use the expression : “He suffers from rhotacism”.

 

Origin of the Expression:

The origin of the term “Rhotacism” comes from the Greek letter rho (Ρρ), which is the equivalent of the English letter “R.” In linguistics, one famous example of rhotacism is the “Winchester R,” often associated with upper-class British accents.

Examples of use:

  1. Colloquial: “My friend has trouble pronouncing R sounds, and it’s especially noticeable when he says words like ‘red’ or ‘right’.”
  2. Formal: “He suffers from rhotacism, so his ‘R’ sounds often come out as ‘W’.” 

Traduzione in italiano:

In termini colloquiali, l’espressione italiana “Ha la erre moscia” si esprime comunemente come “ha difficoltà a pronunciare il suono della R.” È un modo informale per descrivere la condizione di rotacismo, un disturbo del linguaggio in cui una persona ha difficoltà a pronunciare correttamente il suono della “R”. In un linguaggio più formale, possiamo usare l’espressione: “Soffre di rotacismo.”

Esempi d’uso:

  1.   “I can’t meet you for lunch today; I’m snowed under with work.”
  2.   “She’s snowed under with assignments and barely has time to sleep.”
  3.   “We’re all snowed under right now because of the upcoming deadline.”