Another problem picturing languages as distinct nodes is the idea of linguistic uniformity within a proto-language, despite the existence of dialects within even small language communities (However the real life implications of this simplification are doubted) \cite{campbell2004}.  
Analogy can be a difficult problem to overcome, a random change in a word or word feature can make it sound like a fg  
Words are often borrowed from other languages, in English they and them originates from Norse, and the word taboo is borrowed from Tonga; the words are likely bound to the linguistical rules of the old language rather than the new.

Genetic linguistic research methods

Biologists have leaned into the similarities between linguistics and genetics and used . Evolutionary models can take into account areal diffusion (horizontal transmission)

Bayesian Phylogenetics

Modern day linguistical phylogenetic methods are usually based on Bayesian Markov Chain Monte Carlo (MCMC) methods, in essence a mathematical model that can extrapolate
To explain it we will start with Bayes' theorem
\(\left(P\left(H\ \right|\ E\ \right)=\frac{\left(P\left(E\ \right|\ H\right)\ \cdot\ P\left(H\right)}{P\left(E\right)}\)

Bayesian phylogenetics & polynesian migration

Bayesian phylogenetics are particularly useful in the field of Polynesian language evolution due to the unique migratory lifestyle of the polynesian peoples. Contact between distal islands was sporadic, and in the case of Rapa Nui, non existent. This largely eliminates the comparative method criticism of linhuisticCurrent theories of Polynesian people's origin fall into two main camps: Express Train theory and the Entangled Bank theory \cite{Kayser_2000}. The more popular theory, Express Train, first put forward by Jared Diamond \cite{Diamond1988}posits that Polynesian migration originated in Taiwan and started relatively recently 3000-1000BCE, and migrating via the Philippines and New Guinea and reaching Melanesia by roughly 1400BCE and reaching Samoa by 900BCE. Entangled Bank theory however puts forward that there was no single 'express train' to Polynesia, it emphasises smaller migration as well as the long cultural and genetic interactions between the Polynesians, Melanesians and East Asians. Newer theories such as Kayser et al.'s Slow Boat theory attempts to marry these two ideas, while supporting a Tawainese origin and rapid migration to Melanesia, then suggests that upon reaching Melanesia migration slowed, and there was a long delay (leading to cultural and genetic admixture) before migration to Polynesia. 
Contemporary linguists have attempted to solve these competing theories using Bayesian inference, an important paper being Language Phylogenies Reveal Expansion Pulses and Pauses in Pacific Settlement , which focuses on how (timewise) the migration took place, both this and Language trees support the express-train sequence of Austronesian expansion.

Criticism of bayesian phylogenetics

\cite{churchill1912} \cite{Walker_2010} \cite{Diamond_2003}\cite{Greenhill_2010}\cite{churchill1911}\cite{Gray_2009}\cite{2013}\cite{Gray_2000}

Conclusion