Swenglish is a colloquial term referring to the English language heavily influenced by Swedish in terms of vocabulary, grammar, or pronunciation.

The name Swenglish is a portmanteau term of the names of the two languages and is first recorded from 1938, making it one of the oldest names for a hybrid form of English. Other colloquial portmanteau words for Swenglish include (chronologically): Swinglish (from 1957), Swedlish (1995) and Sweglish (1996).

Swedish is characterised by a strong word stress and phrase prosody that differs from that of English.

There are words that are similar in meaning and pronunciation, that have different stress patterns. For example, verbs that end with -era in Swedish are often French loanwords, where the French word ends with a stressed -er. The Swedish word gets its stress point at the same place, but this is not true in English. A native Swedish speaker might mispronounce generate by following the pattern of the Swedish generera [jɛnɛˈrěːra].

Swedish is a pitch accent language. Accent 1 is a low-high-low contour and accent 2 is a high-low-high-low contour, with the second peak in the second syllable. This can give Swenglish speakers a "singing" quality to their speech. Particularly when exaggerating their Swedish accent in English, speakers add an extra cadence to their words that most native English speakers lack.

Swedish lacks many common English phonemes. These are sometimes replaced by similar-sounding Swedish phonemes, or other English phonemes that are easier to pronounce. For example, when using the nearest Swedish vowels for the English words beer and bear, a native Swedish speaker might pronounce both as [beːr]. In general, Swenglish will sound very articulated, due to Swedish vowels being more strongly articulated and not as often reduced to schwas.

Swedish also lacks some consonant phonemes common in English, such as voiceless dental fricative /θ/, which is typically realized as labiodental [f] or a voiceless dental stop [t̪], leading to three being pronounced as "free" or "tree". Other missing consonants include voiced dental fricative /ð/, which is typically realized as a voiced dental stop [d̪]), voiced alveolar fricative /z/, which is typically realized voicelessly [s] and voiced palato-alveolar fricative /dʒ/, which is realized voicelessly [tʃ], somewhat more back [ʈʂ], or as a voiced palatal approximant [j] or fricative [ʝ].

There are examples of Swenglish being used in Sweden as a means of brand management. The Swedish telecommunications company Tele2 has long aired commercials with a black sheep called Frank. The pun of the commercials, extolling inexpensive service, is based on the English word cheap, which usually is pronounced as "sheep" by Swedes—hence Frank.