Introduction to the topic and the correct pronunciation of 'Celtic'.

• The host introduces the topic of Celtic influence on the English language.
• Clarifies the pronunciation of 'Celtic', noting the exception for the Glasgow football team.

Discussion on the native inhabitants of Britain and historical migrations.

• Questions the identity of the Native Britons and compares it to the concept of Native Americans.
• Notes that Britain was uninhabited until 12,000 years ago and that all humans are immigrants in a historical context.

Explains various invasions in Britain and insights from DNA evidence and linguistic research.

• Covers the importance of invasions throughout millennia in understanding the influence on the English language.
• Highlights recent findings from DNA evidence and linguistic research that shed new light on the history of Britain's inhabitants.

Details sources used for linguistic evidence and the uncertain timeline of Celtic arrival in Britain.

• References John McWhorter's book and other sources for linguistic evidence.
• Discusses the timeline of the Celts' arrival in Britain and introduces the earliest mention of Celts by Pythius around 330 BC.

Explores the inhabitants and languages of Britain before the arrival of the Celts.

• Describes Britain's prehistoric inhabitants, including Homo sapiens and Neanderthals, and the impact of ice ages on habitation.
• Discusses the Mesolithic and Neolithic periods in Britain, including the transition to agriculture and the genetic origins of the population.

Introduces the migration of the Bell Beaker people and their potential languages.

• Explains the migration of the Bell Beaker people, who brought new technologies and possibly replaced the gene pool of the Neolithic people.
• Discusses the possible languages spoken by the Bell Beaker people, including an Indo-European language, and the implications of DNA evidence.

Analyzes the influence of Celtic tribes on Britain and the languages that emerged.

• Outlines the arrival and integration of Celtic tribes in Britain.
• Describes the proto-Celtic language and its divergences into Brittonic and Goidelic language groups.

Covers the Roman invasion of Britain and the linguistic consequences.

• Details the Roman invasion in 43 AD, the presence of Roman garrisons, and the spoken languages during the Roman era in Britain.
• Explains why Latin did not remain in Britain post-Roman era, unlike in other parts of the Roman Empire.

Discusses the arrival of Anglo-Saxons and the transition to English from Celtic languages.

• Explores the narrative that Anglo-Saxons pushed Celts to the fringes of Britain and the impact on language.
• Challenges the idea that Celts had little influence on the English language, using DNA evidence and the presence of Celtic words in English.

Explores the direct and indirect contributions of Celtic words to the English language.

• Lists a few words of Celtic origin in English and discusses the complexity of determining their origins.
• Mentions the influence of Celtic words on place names and river names in Britain.

Examines the peculiar use of 'do' in English questions and negatives, linking it to Celtic languages.

• Describes the unique and seemingly unnecessary use of 'do' in English, comparing it to other languages.
• Attributes the presence of the 'meaningless do' in English to the influence of Welsh and Cornish.

Analyzes the use of the present continuous in English and its roots in Celtic grammar.

• Details the mandatory use of the present continuous in English to describe actions happening at the moment.
• Notes the similarity of this grammatical structure to Welsh and its uncommon use in other languages.

Concludes with a summary of the significant impact of Celtic languages on English grammar.

• Recaps the evidence for the influence of Celtic on the English language, especially in terms of grammar.
• Acknowledges the substantial but often overlooked impact of Celtic languages on English.